Green’s Dictionary of Slang

dick n.5

[? gypsy use dicked, being watched (cf. dekko n.), dick v.1 or abbr. SE detective; the link to the fictional Dick Tracy (created 1931) is chronologically impossible]
(US )

1. a police officer, usu. male.

[US]F. Hutchison Philosophy of Johnny the Gent 79: ‘[T]hem big cheese coppers thinks nobody's hep to them bein’ dicks who they take off the brass buttons an hide their star?’.
[US]G. Bronson-Howard Enemy to Society 162: The ‘dicks’ ain’t givin’ him no protection, see?
[US]J. Lait ‘Canada Kid’ in Beef, Iron and Wine (1917) 153: A plain-clothes dick nails me wit’ my fingers in a rube’s overcoat.
[US]G. Henderson Keys to Crookdom 373: The dick and the dip saunter off up to the station.
[US](con. 1900s–10s) Dos Passos 42nd Parallel in USA (1966) 290: There was a dick looking into our faces as if he was trying to remember them.
[US]C. McCullers Heart is a Lonely Hunter (1986) 331: He saw the dicks and in a panic he started to run.
[Aus]Cusack & James Come in Spinner (1960) 321: Gotta keep me eyes skinned for Ted next door, he’s just been put on and if you ask me he’s a dark horse. I’ve a feeling he might be in with the dicks.
[US]Hughes & Bontemps Book of Negro Folklore 348: Taxi, taxi, taxi, / Drive me to Tennessee. / He said, Drive me, bubber, / ’Cause the dicks is after me.
[US]B. Jackson Get Your Ass in the Water (1974) 72: He’d turn a few tricks and baffle the dicks, / leavin’ not a clue to find.
[US](con. early 1950s) J. Ellroy L.A. Confidential 100: Sid Hudgens didn’t call so much – he wasn’t a Narco dick now.

2. a detective; thus house dick, the security officer in a hotel, office; store-dick a store detective etc.

[US]G. Bronson-Howard Enemy to Society 293: He turned Stevey up while Steve was workin’ on th’ ‘pete,’ and th’ ‘dicks’ rushed in and glomed him.
[US]J. Lait ‘Charlie the Wolf’ in Beef, Iron and Wine (1917) 26: We’re a fine pair o’ dicks.
[US]M.C. Sharpe Chicago May (1929) 30: The pinch had been made by a store-dick in Carson, Pirie & Scott’s establishment. [Ibid.] 255: The context is often the only clue the crook has in determining the meaning of some words. A dick may mean a detective, or a policeman.
[US] (ref. to late 19C) N. Kimball Amer. Madam (1981) 98: We’d strut in the hotel lobbies, wink at the house dick we knew, but never go for a masher or give the eye to a gentleman.
C.B. Yorke ‘Snowbound’ in Gangster Stories Oct. n.p.: ‘You’re not such a bad guy for being a dick’.
[US]R. Chandler ‘Red Wind’ in Red Wind (1946) 16: I didn’t know either of the dicks. You can be in the detecting business a long time and not know all the men.
[US]R.L. Bellem ‘Heads You lose’ in Dan Turner Hollywood Detective Feb. [Internet] I’m a private dick. That makes me a cop, sort of.
[US]I. Shulman Amboy Dukes 70: I guess you don’t like dicks.
[US]Monteleone Criminal Sl. (rev. edn) 125: house dick A hotel detective.
[US]J. Thompson Swell-Looking Babe 119: Risk Fillmore’s [...] calling the house dick.
[US]R. Prather Scrambled Yeggs 36: I have to carry a gun [...] the girls wouldn’t think I was a private dick if I didn’t.
[US]C. Himes Crazy Kill 77: You’re too smart for us country dicks in Harlem.
[US]C. Himes Rage in Harlem (1969) 51: The [...] plainclothes dicks all had their prisoners in tow.
[UK]R.L. Pike Mute Witness (1997) 145: The house dick knows this Rykind character.
‘Troy Conway’ Cunning Linguist (1973) 46: I shushed her as best I could, using the pillow before she brought the house dicks in on us.
[US]J. Wambaugh Choirboys (1976) 77: Here’s a mug shot of that dude the dicks want for shanking his old lady.
[UK]S. Berkoff Decadence in Decadence and Other Plays (1985) 8: Decided for a hunch to hire a dick with a nose like a Jew / a private detective.
[UK]A. Payne ‘Willesden Suite’ Minder [TV script] 17: You’ve seen it in the movies, they’re called the house dick.
[US]J. Wambaugh Golden Orange (1991) 35: One team composed of police detectives called itself ‘The Swinging Dicks’.
[US](con. 1949) G. Pelecanos Big Blowdown (1999) 207: The house dick, a fat, bald-headed dude who’d given Matty the fisheye from time to time.
[UK]Guardian Guide 5–12 June 81: Hiring a private dick to help locate her natural mother.
[UK]Indep. on Sun. Culture 23 July 3: He’s a black private dick.