Green’s Dictionary of Slang

(orig. US) an informer, also vb. (see cite 1971).

1920		Seattle Star (WA) 12 Aug. 6/7: The informer, the stoolie, the cat-eyed, slippery, soft-footed Judas.
1930		R. Whitfield Green Ice (1988) 32: Talk foolish over the phone – I’ll spot the good words. Some stoolie might happen to be listening in.
1931		C.B. Yorke ‘Snowbound’ in Gangster Stories Oct. n.p.: Don’t get the idea that I was playing stoolie for anybody.
1940		S. Sterling ‘Ten Carats of Lead’ in Black Mask Stories (2010) 225/2: They never caught him. They picked up that dope from stoolies.
1946		Mezzrow & Wolfe Really the Blues 249: One day some stoolie tipped off the cops that Lil was selling hop.
1948		R. Park Harp in South 98: ‘Yer stinking stoolie’, remarked Flo.
1950		Goldin et al. DAUL 213/1: Stoolo. See Stool pigeon.
1953		W. Brown Monkey On My Back (1954) 131: Patrick had screamed that Hector was a ‘stoolie’ and a ‘rat’.
1957		C. Himes Imabelle 52: We let you operate because you’re a stoolie.
1960		C. Cooper Jr Scene (1996) 178: Something funny’s going on, that little stoolie not wanting any drugs.
1965		C. Himes Rage in Harlem (1969) 53: We let you operate because you’re a stooly.
1971		R.D. Pharr S.R.O. (1998) 361: ‘I stoolie for Ginsburg. I tell him who’s doubling up so he can charge them extra’.
1972		G.V. Higgins Friends of Eddie Coyle 133: You’re telling me I gotta turn stoolie permanent.
1981		H. Gould Fort Apache, The Bronx 10: A stoolie had already made the three guys, supplying names, addresses.
1995		I. Rankin Let It Bleed 98: All good policemen had them; anyone who wanted to get anywhere had them: grasses, stoolies, snitches.
2000		Indep. Rev. 2 Feb. 7: If I had asked Ronald Reagan: ‘Were you a stoolie for the FBI in Hollywood?’ he would have told me nothing.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 17/2: big stoolie, the n. an inmate with an especially bad reputation for being an informer.
2010		Codella and Bennett Alphaville (2011) 315: This jerk-off stoolie goes off about you two guys.