Green’s Dictionary of Slang

1. (also rat against) to betray one’s own party or cause; to let someone down.

[1779		Nocturnal Revels I 160: His Lordship had certainly ratté’d more women than all the rest of the peerage put together].
1797		in R.W. Emerson Eng. Traits (1856) 69: The radical mob at Oxford cried after the tory Lord Eldon, ‘There’s old Eldon; cheer him; he never ratted’.
1812		Southey letter 18 May Life and Correspondence III (1850) 341: W- and C-, I doubt not, ratted upon the Catholic question because they expected the Prince [...] would eject Perceval.
1825		Age (London) 15 May 5/2: Notorious Scarlett, that shuffling varlet, Who ratted from Cambridge when no chance he saw.
1826		J. Randolph letter 6 Jan. Life (1851) II 263: It revived the recollection of the ‘ratting’ (as the English phrase it) among the ‘minority-men,’ some twelve or fourteen years ago.
1830		J.W. Croker Croker Papers II (1884) 76: He talked of resigning with his colleagues as a matter of course, but the knowing ones suspect that he will rat. I think not.
1840		R. Barham ‘Lay of St. Aloys’ Ingoldsby Legends (1842) 251: Don’t give too much credit to people who ‘rat!’.
1849		Thackeray Pendennis I 85: Young Mr. Suckling [...] began to speak lightly of Admiral Bowser’s conduct for ratting to Ministers.
a.1859		in Trevelyan Life of Macaulay I 275: I am fully resolved to oppose several of the clauses. But to declare my intention publicly... would have the appearance of ratting .
1860		R.S. Surtees Plain or Ringlets? (1926) 192: Mr Black White [...] is not asked [...] having ratted from the other side.
1870		Stanhope Hist. of England vii 315: The word rat (both the noun and the verb) was just... levelled at the converts to the Government of George the First, but had by degrees obtained a wider meaning, and come to be applied to any sudden and mercenary change in politics [F&H].
1885		Bulletin (Sydney) 14 Feb. 6/1: A new Government was in course of formation, and as Groom had, as invariably happened, ratted with great effect, and helped to put out the previous Government, the question arose what should be done for him in the allotment of offices. [Ibid.] 11 Apr. 14/2: The ‘damnedest thing’ looks nice, Sir John, / Sometimes, as we must all agree; / But better rat for vice, Sir John, / Than for a bastard chivalry.
1895		Truth (Sydney) 19 May 3/3: On Tuesday next Wise undertakes to define and defend his decision. Will he ‘rat’ back again?
1900		L.A. Eve. Express 22 Nov. 🌐 He failed to charge all that traffic would bear and therefore ‘ratted’ against his craft.
1901		Sydney Sportsman (Surry Hills, NSW) 22 May 1/6: When one’s outed by the stewards / [...] / He’ll be ratted by the others, / Who will cop his everything.
1912		N.Z. Truth 21 Sept. 6/4: Whitley, who sat as [a] Conservative MP [...] ‘ratted’ and became a Liberal.
1918		C.J. Dennis ‘The Joy Ride’ in Backblock Ballads 102: The car was there an’ oil to spare / To rat would be a sin!
1922		Joyce Ulysses 571: Most of all he commented adversely on the desertion of Stephen by all his pubhunting confrères, a most glaring piece of ratting on the part of his brother medicos under all the circs.
1923		‘Sapper’ Jim Maitland (1953) 188: You’re right, old Dick. I did rat this morning. I’ve never been in such a funk in my life.
1947		C.S. Montanye ‘Frozen Stiff’ in Popular Detective Mar. 🌐 They thought he’d ratted, and they decided to even up.
1951		D. Stivens Jimmy Brockett 218: Note how many of them ‘ratted’ in a crisis and sold out the working-class.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 450: Carlos said don’t call Arden — don’t rat our Cuban runs.
2014		Young M.A. ‘Brooklyn (Chiraq Freestyle’ 🎵 Heard niggas out here rattin’ so I had to set up my mouse traps.

2. to change sides.

1848		Thackeray Vanity Fair 414: He might have been a Peer if he had played his cards better. Mr. Pitt had nearly made him; but he ratted always at the wrong time.
1865		H. Kingsley Hillyars and Burtons (1870) 276: I’m not a-going to rat. I’ll stick by you faithful.
1900–10		Stephens & O’Brien Materials for a Dict. of Aus. Sl. [unpub. ms.] 127: RAT, TO: To desert a politrical party when their fortunes are waning.

3. (orig. US, also rat out) to inform on, to betray; thus n. an act of betrayal.

1885		‘Lela’ in Maitland Mercury (Aus./NSW) 31 Mar. 2: The arch gonnoff is dusty, you’d better wish. If he rats you are a prate roost, you’ll get put to bed with a shovel.
1918		H. Simon ‘Prison Dict.’ in AS VIII:3 (1933) 31/1: RAT. 1, v. To squeal or tattle.
1930		R. Whitfield Green Ice (1988) 208: ‘Ratted it, you did!’ she muttered.
1931		C.W. Willemse Behind The Green Lights 281: He warns of the penalty that comes to the gangster who ‘rats’ when the police get rough.
1947		I. Shulman Amboy Dukes 45: Don’t rat to the cops.
1952		J. Jones From Here to Eternity (1998) 800: Nobody would rat.
1957		C. Himes Imabelle 152: Jodie thought I’d ratted to the police.
1965		C. Himes Rage in Harlem (1969) 153: [as 1957].
1968		J. Alard He Who Shoots Last 28: ‘Didn’t think no one ’ed rat on a kid. Wot a rotten germ’.
1979		E. Torres After Hours 36: He would look half so good if I’d ratted at the trial.
1990		S. Morgan Homeboy 21: If he ratted inside, he’ll rat twice as fast on the street.
1994		J. Wambaugh Finnegan’s Week 260: The porky dude’ll rat off the little Mexican, I bet.
1999		K. Sampson Powder 28: We wanted to get away before he takes our dabs and rats to the soshe ...
2003		A.N. LeBlanc Random Family 77: Jessica briefed George [...] who planned to plead guilty, who else might rat.
2008		Simon & Collins ‘Not for Attribution’ Wire ser. 5 ep. 3 [TV script] I’m gonna tell Landsman. Yeah. You keep on with it, I’m gonna rat you out.
2010		(con. 1973) C. Stella Johnny Porno 246: He was thinking ahead of a potential disaster; if Nancy broke down and ratted him out.
2010		(con. 1973) C. Stella Johnny Porno 257: I don’t want the money [...] And I won’t rat.
2013		K. Sampson Killing Pool 33: It’s only a matter of time before he rats me out to Thompson.
2014		T.I. ‘Paperwork’ 🎵 Uncle Quint ain’t nowhere to be found / Later we learn that someone ratted him out.
2015		L. McInerney Glorious Heresies 118: [H]e doesn’t rat him out and he doesn’t hit him back and he sure as shit doesn’t take responsibility.
2018		G. Disher Kill Shot [ebook] ‘Rat me out, would you? Fucking little maggot’.
2020		D. Winslow ‘Paradise’ in Broken 262: ‘I’m not ratting Gabe out [...] He’s still my brother’.
2021		J. Ellroy Widespread Panic 153: I ran through the rat-out. One riff rang false.
2021		C. Hammer Opal Country 248: ‘You’re not a rat, are you, Lucic? You wouldn’t rat us out to the media’.

4. (Aus./N.Z.) to steal, to ransack; esp. as ratted, (of people) robbed or (of objects) stolen [note mining jargon ratter, one who steals one’s finds].

1906		Sun. Times (Perth) 30 Sept. 4/8: She don’t ’ave ter chew an’ chafe / [...] / As the lodger rats the safe.
1910		Sun. Times (Perth) 22 May 2nd sect. 12/5: Guarantee I’d rat a sky-rocket slicker than any of them old-timers.-Pickpocket Pete.
1918		Aussie (France) 6 Aug. 2/1: Well, he told me that the Digger who captured him ratted every darned thing he had before handing him over to me, except his identification disc, which he didn’t notice.
1921		(con. WWI) E. Lynch Somme Mud 20: We ‘rat’ a lot of hay from a shed to sleep on. [Ibid.] 296: Fritz is surrendering in droves, We leave them for our mopping-up parties to gather up, and rat.
1925		(con. WWI) Fraser & Gibbons Soldier and Sailor Words 236: Rat, To: To steal. To search a dead body.
1930		J. Lait Put on the Spot 76: His mob an’ Kinky’s wouldn’ rod nor rat so long as the boys stayed on the reservations.
1932		Sun. Mail (Brisbane) 13 Nov. 20/8: Similarly no one ever thieves or robs in the underworld; they ‘rat’ or ‘hoist’.
1951		(con. 1941) E. Lambert Twenty Thousand Thieves 71: Since when has it been wrong to rat a bloody Hun?
1959		D. Niland Big Smoke 106: I don’t give a hang about the poorbox or the attempt to rat it.
1973		(con. 1930s) F. Huelin ‘Keep Moving’ 42: To rat another man’s swag was unthinkable — the lowest crime in the hobo code.
1977		(con. 1941) R. Beilby Gunner 62: Pepsodent always ratted stiffs for souvenirs.
1983		J. Byrell (con. 1959) Up the Cross 92: ‘Someone’s out in amongst your plants [...] Thery’re ratting your shrubs, I reckon’.
1988		McGill Dict. of Kiwi Sl. 91/2: rat steal or plunder.
1999		www.abc.net.au 22 June 🌐 The Miners’ Association claims the ratters are selling stolen opal to organised crime syndicates in Melbourne.
2003		McGill Reed Dict. of N.Z. Sl. [as cit. 1988].
2014		J. Thomas blackopaldirect.com 🌐 These bottom-dwelling lurkers are known in Lightning Ridge as ratters. This is because they gather their information and then break into peoples mines at night and dig out the opal.
2021		C. Hammer Opal Country 1: [T]he four men proceed in silence, ratters united by greed and needs unspoken, by quiet desperations,.

5. (US campus) to tease, to ridicule.

1997

Eble Campus Sl. Apr. 7: rat – make fun of: ‘I felt sorry for him because everybody there started ratting him’.

6. (US black) to go out in pursuit of women.

2000

Ebonics Primer at www.dolemite.com 🌐 rattin’ Definition: when you’re on the prowl for a few ghetto bitches Example: Yo, I be rattin’ for a few nasty waties who wanna get up on this pimp pop.