Green’s Dictionary of Slang

copper n.

1. (US, also copperskin, Mr Copperskin) a Native American; also attrib.

[US] in Travels Amer. Col 523: He said there would be Copers [sic] and White people present at the meeting [DA].
[US]C.F. Hoffman Greyslaer II 26: ‘Go on, go on, Kit; d’y say a dozen Injuns?’ ‘Yes, uncle, not a Copperskin less’ [DA].
[US]Eaton Democrat (OH) 13 Mar. 2/5: I feel disposed to defend [...] the principle of music, no matter by it may be taught, whether it be negro, white man, Hottentot or copperskin.
T. Winthrop Canoe and the Saddle (1883) 146: The five copper-skins first eyed me over with lazy thoroughness.
[UK]London Standard 2 Aug. 5/3: General Sheridan [...] is an extreme authority to cite on the subject of the treatment of the copperskins.
[UK]Leamington Spa Courier 7 May n.p.: [He] was evidently well acquainted with the not over-prepossessing copper-skin.
[UK]Gloucester Citizen 4 Feb. 3/3: On almost every Indian reservation there is a court of Indian offences presided over by a Copperksin judge.
S.E. White Silent Places 72: What the hell do we care for a lot of copper-skins from Rupert’s House!
[US]Owosso Times (MI) 17 Mar. 2/2: Listen to the tales of B.O., of his great hunting trips and trading with Mr Copperskin.
[UK]G. Kersh Fowlers End (2001) 56: Copper Baldwin. It would not have surprised me if he had turned out to be a Yaqui Indian in war paint.

2. as money.

(a) a halfpenny; thus coppers, mixed pennies and halfpennies.

[UK]G. Parker Life’s Painter 133: What, no copper clinking among you, my hearties?
[Ire] ‘Luke Caffrey’s Ghost’ in Chap Book Songs 3: So ’fore all your coppers are spint, / Take warning in time, as I charge you.
[UK]‘T.B. Junr’ Pettyfogger Dramatized II iii: Our calling would not be worth a copper, but for such gentry as him.
[UK]Sporting Mag. Mar. XXIII 352/1: Tom licks him, I’ll lay you a copper.
[US]C.A. Davis Letters of Major J. Downing (1835) 45: They tell me it [i.e. a bank-note] ain’t worth a copper.
[UK]C. Selby London By Night I ii: Got a copper for the sweeper.
[UK]A. Mayhew Paved with Gold 87: They’ll all say they ain’t got no coppers, but don’t believe it and stick to ’em.
[UK](con. 1840s–50s) H. Mayhew London Labour and London Poor III 64/2: The novelty of the exhibition ensured its success, and the ‘coppers’ poured in.
[US]W.H. Thomes Bushrangers 115: De man might go off and no pay me. We has to look arter all de coppers, or we be ruined.
[UK]G.R. Sims Three Brass Balls 160: It was bad enough to be so pushed that the flat-iron had to go for a few coppers to carry on with.
[Aus]Morn. Bulletin (Rockhampton, Qld) 18 July 2/6: A half-penny [...] may find the following; ‘bawbees,’ ‘browns,’ ‘camden town,’ ‘coppers,’ ‘ flatch,’ ‘gray,’ ‘madge.’ ‘make,’ ‘mag or maga,’ ‘posh,’ and ‘rap’.
[UK]C. Rook Hooligan Nights 49: Blackmailing is [...] only to be resorted to when you haven’t one copper to rub against another.
[UK]New Boys’ World 22 Dec. 76: The I-talian disappeared without leaving me a copper.
[UK]N. Douglas London Street Games 124: They asked me to play BANKER (just for a lark, they said) and got five coppers out of me in about half as many minutes.
[Ire]S. O’Casey Juno and the Paycock Act II: Fond of his pint – well, rather, but hated the Boss by creed / But never refused a copper to comfort a pal in need.
[UK]J. Curtis They Drive by Night 24: ‘Tea, please,’ he said, banging two coppers down on the counter.
[UK]S. Jackson Indiscreet Guide to Soho 59: The million-pound epics yield only coppers to the rank-and-file of the industry. [Ibid.] 62: They don’t give you a chance to earn an honest copper.
[UK]I. & P. Opie Lore and Lang. of Schoolchildren (1977) 299: Please can you spare me a copper or two? / If you haven’t got a penny a ha’penny will do.
[UK]P. Willmott Adolescent Boys of East London (1969) 157: I said to Michael, ‘Have you got four coppers. I want them for the telephone box?’ The copper went absolutely mad.
[UK]J. Sullivan ‘Healthy Competition’ Only Fools and Horses [TV script] I’m not going to mess around with coppers.

(b) (US) a cent.

[US] in J.H. Hickcox Amer. Coinage (1858) 102: All Coppers by him coined, shall be in pieces of one third of an ounce [DA].
[US]J. Neal Brother Jonathan II 137: It amounted to one dollar and a quarter, ‘hard money’; or ten shillings ‘York currency’ — or two hundred and fifty half coppers.
[US]H.C. Todd Notes 7: The word coppers designates cents [DA].
[US]Durivage & Burnham Stray Subjects (1848) 104: Here’s yure contemptible copper.
[US]J.H. Green Reformed Gambler 34: This meeting was held in the Methodist Church, which for me was most unfortunate, as the house was crowded with revivalists, who left their coppers at home, or kept them close in their pockets.
[US]A.H. Lewis Boss 7: I knew a way to pick up coppers.
[US]C. Himes ‘With Malice Toward None’ in Coll. Stories (1990) 50: Two coppers remained like two eyes mocking him.
[US]E.M. Kahn Cable Car Days 70: A well-known lady living on Nob Hill [...] boarded a California Street cable car and produced five coppers in payment of her fare [DA].
[US]Wentworth & Flexner DAS.

(c) in pl., wages.

[UK](con. 1930s) Barltrop & Wolveridge Muvver Tongue 17: ‘Coppers’ has been used for wages collected when a person leaves or is sacked from a job – ‘You can have your cards and coppers’.

(d) (W.I.) in pl., money in general.

[WI]F. Collymore Notes for Gloss. of Barbadian Dial. 35: Coppers. [...] the word is also used in a sense similar to spondulicks, dough, etc.: as He can buy a car; he got the coppers.

3. a police officer [the SE copper badges carried by New York City’s first police sergeants; patrolmen had brass badges, lieutenants and captains silver ones; strengthened by cop v. (1)].

[UK]R. Nicholson Cockney Adventures 3 Feb. 107: ‘Do it at vonce, else the coppers ’ill come,’ said he of the short pipe.
[US]‘Ned Buntline’ Mysteries and Miseries of N.Y. I 36: In Boston, the coppers there aint half so keen with their peepers as they are here!
[UK]Chester Chron. 25 June 6/5: If the ‘coppers’ or police officers are too wide-awake [...] the twisting dodge is tried.
[US]N.E. Police Gaz. (Boston, MA) 12 Oct. 6/1: The Boston coppers are after him.
[UK]Manchester Courier 13 June 4/4: ‘Copper’... a slang name for a policeman derived from cop, which is a well known and generally used vulgarism for ‘catch’ .
[UK]Leaves from Diary of Celebrated Burglar 6/1: We were all assembled over our ‘lush’ [...] when the ‘office’ was given that the ‘coppers’ were ‘on’.
[UK]Five Years’ Penal Servitude 236: I daresay the coppers quite expected us the next night, and looked out for us.
[UK] ‘Blooming Aesthetic’ in Rag 30 Sept. n.p.: A tell-a-good-whopper young man, / A slogging-a-copper young man.
[UK]Ally Sloper’s Half Holiday 7 June 47/2: To others Samuel Hardstaff is a peeler, a reeler, a copper, a Bobby, a Robert, an unboiled lobster, or a slop, but to cook he is Mr Policeman.
[Aus]Bulletin (Sydney) 23 Aug. 19/2: I heard the copper say – / ‘Drunk, yer worship, quite incapable, unconscious, an’ I ran / Him into quod for safety.’ Said I, ‘Oh, Cigar divan.’.
[UK]C. Rook Hooligan Nights 42: A copper took him off to the police station.
[US]Bliss From Boniface to Bank Burglar in Hamilton (1952) 45: The fat, thin, great, small, long and short hand of the copper was held out from all sides.
[UK]A. Conan Doyle His Last Bow in Baring-Gould (1968) II 798: ‘The man was mad.’ [...] ‘It’s enough to make a man bughouse when he has to play a part from mornin’ to night, with a hundred guys all ready to set the coppers wise to him.’.
[US]J. Callahan Man’s Grim Justice 35: ‘There never was a copper that couldn’t be bought,’ she said.
[US](con. 1920s) J.T. Farrell Young Manhood in Studs Lonigan (1936) 201: He swung the butt of it down, like he was cracking a copper’s skull.
[UK]G. Kersh Night and the City 27: Coppers! That’s wot we pays ‘em for — to take the bleedn strike-me-dead out of yer children’s mouf.
[Aus]K. Tennant Foveaux 142: It would just serve you right, if we let you loose, and you did stouch a copper and get pinched.
[US]Mezzrow & Wolfe Really the Blues 32: I couldn’t figure out why a copper would go poking his nose under the seat of a respectable-looking cab.
[UK]J. Arden Live Like Pigs Act I: You put us. Coppers put us – all the lot of narks.
[US]C. Himes Crazy Kill 31: Sergeant Brody asked them routine questions in a passionless copper’s voice.
[UK]C. Wood ‘Prisoner and Escort’ in Cockade (1965) I ii: All coppers are [...] bastards.
[UK]P. Theroux Family Arsenal 27: The coppers’ll be on to you before long and have you in the nick.
[UK](con. 1950s–60s) in G. Tremlett Little Legs 4: Dixie boy, here comes a copper.
[UK]Indep. Information 21–27 Aug. 59: He was everybody’s idea of what a copper should be.
[UK]Guardian Guide 22–28 Jan. 9: ‘That pickaxe is covered in blood, isn’t it?’ asked one copper.
[Aus]R.G. Barrett Rosa Marie’s Baby (2013) [ebook] Between that copper pulling me over, and Uriah [...] I’ve been well and truly fucked.
[UK]S. Kelman Pigeon English 87: F— off before I call the coppers!
[Aus]G. Gilmore Headland [ebook] ‘My mistake, she’s a bleeding copper’. 29 Nov. [Internet] The police are nicer to the girls now. We’ve got a community copper now in Holbeck and she’s so lovely.

4. attrib. use of sense 3.

[Aus]Sydney Sportsman (Surry Hills, NSW) 5 Dec. 4/1: Persons that, in ‘copper’ parlance, are ‘well known to the police’.
[US]N. Algren Never Come Morning (1988) 24: Even cops ’d come around [...] he’ll tell ’em they can stay around ’n have a beer so long as they don’t try no smart copper tricks.

5. an informer, whether in or out of prison.

[UK]M. Davitt Leaves from a Prison Diary I 22: They [i.e. senior criminals] never ‘round’ upon each other, while they hold all ‘coppers’ (prison informers) in detestation.
Winnipeg Trib. (Manitoba) 9 Dec. 19/1: ‘Copper’ — [...] ‘a crook’ who betrays another crook to the police.
[UK]S. Scott Human Side of Crook and Convict Life 152: One of the lags of our party, who had a reputation as a copper (or tale-bearer), saw the mist rising.
[UK]Thieves Slang ms list from District Police Training Centre, Ryton-on-Dunsmore, Warwicks n.p.: Copper: Informant.
[US]Goldin et al. DAUL 50/1: Copper. [...] 3. An informer; a despicable person.
[US]Wentworth & Flexner DAS.
[NZ]G. Newbold Big Huey 122: The next time the screw tries to come any shit, you just tell him to do his own dirty work [...] He’s trying to make coppers of all of you.
[Aus]Tupper & Wortley Aus. Prison Sl. Gloss. [Internet] Copper. 2. An informer.

6. (US prison) good conduct marks.

[US]Hopper & Bechdolt ‘9009’ (1909) 7: ‘Hang on to your copper,’ he murmured. [Ibid.] 38: He would have remaining to serve only 1760 days. 1760 – if he held his copper. He had held it [...] These calculations had become a mania with him. He would reduce to days his original sentence, then to days his copper, then his original sentence minus his copper, then his original sentence minus his copper minus the days served.
[US]Jackson & Hellyer Vocab. Criminal Sl. 25: copper [...] Current amongst prison habitues. The commutation or good time allowed prisoners for good behavior. Example: ‘You grab one month copper off the first year’.
[US]G. Henderson Keys to Crookdom 401: Coppers. Credits given for good behavior in prison.
[US]San Quentin Bulletin in L.A. Times 6 May 7: COPPER, good prison records.
[US]Goldin et al. DAUL 50/1: Copper. [...] 2. (Many prisons) Time off for good behavior; good time.
[US]Wentworth & Flexner DAS 123/1: copper Time subtracted from a prison sentence because of good behaviour; time off a prison sentence because the prisoner has informed on his co-criminals after the sentence was imposed.

7. a private detective.

[US]D. Hammett ‘The Creeping Siamese’ in Penzler Pulp Fiction (2006) 20: The first man I ran into was [...] Pederson, the house copper.

8. (US Und./police) ext. of sense 6, parole.

[US]R. Chandler Farewell, My Lovely (1949) 35: We got a wire from the Oregon State pen on him [...] All time served except his copper.

9. see copperhead n. (3)

In compounds

copper-hearted (adj.) (US Und.)

1. being an informer by nature; thus turn copper-hearted, to betray one’s associates.

[US]Cleveland Morn. Leader (OH) 23 Mar. 1/2: Judas [...] became copper-headed and copper-hearted and betrayed his Lord to the Confeederate Priests.
Jackson Dly News (MS) 1 Apr. 7/3: Crook Chatter [...] [A] dip who has been turned up because some woman ‘tipped her mitt’ [...] denounces her as a ‘copper-hearted moll’.
[US]Pacific Reporter 223 212/2: ‘I am going to have you arrested’ [...] ‘You copper-hearted son of a bitch; I will cut your head off’.
[US]Amer. Mercury 21 455: Copper-hearted, adj.: To be by nature a police informer. ‘Is that broad copper-hearted? And how!’.
[US]A.J. Pollock Und. Speaks.
[US]Monteleone Criminal Sl. (rev. edn).
[US]C. Hamilton Men of the Und. 287: His hoodlum pals give him a quick brush-off, considering him a copper-hearted flunky.
[US]‘Iceberg Slim’ Pimp 37: One thing about ‘Party’ he wasn’t copper-hearted. He never tipped my name to the heat.

2. mean, vicious, adhering to the negative stereotypes of the police.

[[US]Edgefield Advertiser (SC) 29 June 2/2: The Copper-hearted Chicken! We have been shewn a dirty copper cent which someone plmed off on the ladies of the Methodist Church].
[US]Ersine Und. and Prison Sl.
H.R. Cayton Long Old Road 171: ‘I don’t mean you don’t do your work well, but you don’t think like a policeman.’ [...] ‘You mean I’m not copper-hearted?’.
New Strategies for Public Affairs Reporting 157: They [i.e. reporters] must be able to convey police attitudes without being either ‘copper-hearted’ or overly critical.
copper house (n.)

a police station.

[UK]J. Curtis Gilt Kid 133: Just imagine getting a rub-down at the copper-house.
copper jitters (n.)

(US drugs/Und.) excessive fear of the police, verging on obsession.

[US]‘William Lee’ Junkie (1966) 65: Pushing junk is a constant strain on the nerves. Sooner or later you get the ‘copper jitters’ and everybody looks like a cop.
copper john (n.) (US Und.)

1. a prison warden.

[US]Wash. Post 3 July 3/1: Yer right, red [...] A little stretch up at Copper John’s is the only thing fer Hoppy’s habit.

2. a prison.

cited in R. Sampson Yesterday’s Faces (1987) 83: ‘Liberty For Sale’ (December 4, 1926) allows Big Scar to break into ‘Copper John’ — the Blackstone Penitentiary.
[US]A.J. Pollock Und. Speaks 26/1: Copper John, a penitentiary.

3. an informer.

[US]N. Algren Man with the Golden Arm 184: Copper johns, double clockers, lush workers and mush workers, deadpickers and turncoats.
copper shop (n.) [shop n.1 (1)]

a police station .

R. Marsh in Service of Love 321: I am going to use the telephone to get into communication with the nearest copper-shop; otherwise police-station.
T. Fallon River Police 217: Wapping Police Station was hit, the boatyard being put out of action temporarily, and a large wharf on the other side of the station was razed to the ground. So the ‘copper shop’ had a providential escape.
[UK]Partridge DSUE (8th edn) 254/1: since ca. 1910.
[UK]J. Stevenson London Bridges (2001) 282: If we’re going to a copper-shop, we’d better be road-legal.
coppershy (adj.)

(US Und.) used of one who is terrified of the police.

[US](con. 1905–25) E.H. Sutherland Professional Thief (1956) 30: The fact that he is a drunkard, lazy, a dope fiend, coppershy [...] or any of many other characteristics.
[US]C. Hamilton Men of the Und. 321: Coppershy, Afraid of the police.
copperskin (n.)

see sense 1 above.

copper’s nark (n.) [nark n.1 (1)]

a police informer.

[UK]Dundee Courier 4 Sept. 3/6: In a case tried [...] this week, a witness incidentally said [...] a ‘copper’s nark’ meant a person who gives information to the police.
[UK]Manchester Eve. News 30 Sept. 2/5: It was rumoured that the deceased had been stabbed because he was a spy against the Fenians, and was known as a ‘copper’s nark’.
[UK]J.W. Horsley Jottings from Jail 24: Another complains that he is ‘put away by Charly Start, the Copper’s Nark’.
[UK] Answers 20 July 121/1: He instructed me... on no account to appear to be anxious to pry into their secrets, lest I should be mistaken for a copper’s nark, i.e., a person in the pay of the police [F&H].
[UK]Daily Tel. 18 Oct. in Ware (1909) 92/1: Upon this the prisoner, who was standing by, accused witness of being a ‘copper’s nark’ (i.e., a police spy), and dealt him several severe blows.
[UK]G.R. Sims In London’s Heart 293: You’ve done this, you skunk! [...] You’ve turned coppers’ nark!
[UK]W.W. Jacobs ‘Self-Help’ in Monkey’s Paw (1962) 234: ‘Narks,’ says the ’tec; ‘coppers’ narks.’.
[UK]T. Burke Limehouse Nights 135: She was known to be a copper’s nark.
[US]Manchester Democrat (IA) 5 July 7/5: Will you shake hands — with a copper’s nark?
[UK]C.G. Gordon Crooks of the Und. 69: A ‘grass’ is the term for ‘copper’s nark’ in the underworld to-day.
[Ire]Eve. Herald (Dublin) 9 Dec. 4/6: There are many terms used by crooks to describe this person [i.e. an informer] who is known as ‘copper’s nark,’ ‘squeaker,’ and ‘grasshopper’.
[UK]R. Hyde Nor the Years Condemn 211: Come on, you copper’s nark.
[UK]T.K. Martin Z Cars (1963) 112: I’m no copper’s nark.
[Aus]F.J. Hardy Outcasts of Foolgarah (1975) 27: Brown Tongue decided to play his well-known role of copper’s nark.
[UK]J. Sullivan ‘May the Force be with You’ Only Fools and Horses [TV script] My Mum’d turn in her grave if she knew I’d become a copper’s nark!
[Aus]G. Seal Lingo 50: Other terms that remained fairly firmly in the little lingo of the crims included do a bust, to escape from custody; darbies for handcuffs [...] and copper’s nark, meaning a police informer.
[UK]N. Barlay Hooky Gear 231: Registered informants, coppers narks, grasses, call them what you will.
copper-stick (n.) [note SE copper-stick, used to stir a laundry]

1. a police truncheon.

[UK]Partridge DSUE (8th edn) 254/1: from ca. 1880.

2. the penis [fig. use of sense 1 + stick n. (1a)].

[UK]Farmer & Henley Sl. and Its Analogues.
[UK]Farmer Vocabula Amatoria (1966) 32: Baton, m. The penis; ‘the copper-stick’.
[US]Maledicta IV:2 (Winter) 194: We also find the policeman represented with his truncheon, billie, night stick or copper stick (which is also a housewife’s tool of the last century).

In phrases

blow one’s copper (v.)

(US prison) to lose the reduction in sentence that would otherwise accrue for good conduct; thus hold one’s copper, to maintain good conduct.

[US]Hopper & Bechdolt ‘9009’ (1909) 38: He would have remaining to serve only 1760 days. 1760 – if he held his copper. He had held it.
[US]San Quentin Bulletin in L.A. Times 6 May 7: BLOW YOUR COPPER, to lose good time prison credits.
[US]C.B. Davis Rebellion of Leo McGuire (1953) 227: I began serving my life sentence in Sing Sing and the very first resolution I made was that I was going to keep my good behaviour, or what good old Danny [...] used to call holding your copper.
call copper (v.) (also scream copper)

(UK Und.) to inform the police.

[[UK]Sheffield Eve. Teleg. 4 Nov. n.p.: A schoolboy described how he secured the parcel containing the body, and how he proceeded to call a ‘copper’].
[US]R. Chandler ‘Nevada Gas’ in Spanish Blood (1946) 139: I called copper on Mops Parisi.
[US]F. Brown Dead Ringer 75: You could see the idea of calling copper hurt him.
[US]R.E. Alter Carny Kill (1993) 105: Nobody should call copper because of it.
[Aus]D. Ireland Chantic Bird 114: You’ve got to watch the citizens. They’ll call copper if you look sideways at them.
[US]E. Bunker Mr Blue 83: He still might scream copper and get us closed down.
come (the) copper (v.)

to become an informer.

[UK]Thieves Slang ms list from District Police Training Centre, Ryton-on-Dunsmore, Warwicks n.p.: Come copper: To give information to the Police.
[UK]E. Raymond Marsh 282: Your great bully [...] was here yesterday afternoon trying to bribe me to come copper about a burglary.
[UK]J. Curtis They Drive by Night 122: You bin and shopped me. That’s what you done. Come the copper. You dirty little bitch.
[UK]J. Curtis Look Long Upon a Monkey 27: He didn’t expect a tumble, and if this Irish geezer didn’t reckon the lark he wasn’t the sort to come the copper.
cry copper (v.)

to raise the alarm.

[[UK]S.F. Hatton London’s Bad Boys 21: There is only one thing for it, and that is to cry ‘Copper’ in a long-drawn-out yell as warning to all others, and bolt for it as hard as possible].
R. Heinlein Double Star 25: Look, old son, I might twist your arm a bit and let you think that I would cry copper — but I never would.
[UK]G.W. Target Teachers (1962) 26: As she’s cried copper so often she bloody well had to.
[UK](con. 1980s) N. ‘Razor’ Smith A Few Kind Words and a Loaded Gun 285: If you go mob-handed to an after-hours drinker and try your luck starting fights with strangers, how can you turn around and cry ‘copper’ when you come unstuck.
give birth to a copper (v.) (also give birth (to it)) [fig. use of sense 3 above]

(Aus.) to defecate.

[Aus]Tupper & Wortley Aus. Prison Sl. Gloss. [Internet] Give birth (to it). To defecate.
[Aus]G. Seal Lingo 88: Bodily functions do not escape the Lingo. Defecation may be unappealingly described as giving birth to a copper (a policeman), or choking a darkie.
half-copper (n.)

(US) a half-cent.

[US]J. Neal Brother Jonathan II 137: It amounted to one dollar and a quarter, ‘hard money’; or ten shillings ‘York currency’ — or two hundred and fifty half coppers.
holler copper (v.) (also holler cop, holler police, yell copper, squeal copper(s)) [holler v. (1)/SE yell/squeal (on) v. (3)]

to inform.

[US]D. Runyon ‘A Chilly Looking Blond’ in Brookhouser These Were Our Years (1959) 210: Mrs. Snyder and Gray have been ‘hollering copper’ on each other.
[US]D. Runyon ‘Dream Street Rose’ in Runyon on Broadway (1954) 45: He is not going to holler copper about it.
[US]Black Mask Mar. XXII 10: Not my contract. I holler police. I squawk to Jim Farley.
[Aus]K. Tennant Joyful Condemned 21: Don’t let’s have any blues [...] You know how the brush are? Screaming and yelling copper at the least little thing.
[US]B. Schulberg On the Waterfront (1964) 246: You mean holler cop? Are you kiddin?
[Aus]F.J. Hardy Yarns of Billy Borker 61: Some mug is bound to squeal coppers sooner or later.
[US](con. c.1900) J. Thompson King Blood (1989) 25: She tipped the ‘fool’ she had roped, and the fool hollered copper.
[US]T. Thackrey Thief 191: Give the girl a silver dollar; you didn’t holler copper.
[US](con. 1930s) N. Algren ‘The Last Carousel’ in Texas Stories (1995) 140: When hit with the swag when the hooks were out, they could take a drop without hollering cop.
[US]D. Woodrell Muscle for the Wing 188: I didn’t holler cop.
[Can](con. 1920s) O.D. Brooks Legs 179: We hightailed it too, in case he hollered copper.
play copper (v.)

(UK Und.) to inform (on).

[UK]D. Stewart Wild Tribes of London in Illus. Police News 18 Jan. 12/1: Once, after a devil of a row, she played copper — nosed on me.
put the copper on (v.)

(UK Und.) to inform against.

[UK]D. Stewart Devil of Dartmoor in Illus. Police News 22 Oct. 12/2: ‘So you’ve nosed, have you [...] Well, you’ll never put the copper on anyone else’’.
turn copper (v.)

(US) to become an informer.

Jackson Dly News (MS) 1 Apr. 7/1: Crook Chatter [...] ‘I’d like to know who turned “copper” and “tipped his mitt”’ .
[UK]S. Scott Human Side of Crook and Convict Life 23: Turn ‘copper’! [...] No bloomin’ fear! Not if it means twenty years.
[US]J. Black You Can’t Win (2000) 271: Annie, too ready to believe herself ‘a woman scorned,’ tuned copper on me.
[US]J. Black ‘A Burglar Looks at Laws and Codes’ in Harper’s Mag. CLX 311: He so hates the law, and the brass buttons and stars which to him are its symbol, that even in death he won’t ‘turn copper’.
[US]Ersine Und. and Prison Sl.
[US]Goldin et al. DAUL 228/2: Turn copper. To desert the underworld and assist the authorities by informing against one’s erstwhile associates.