Green’s Dictionary of Slang

1. an informer.

1821		D. Haggart Autobiog. 125: He was a complete geach and squeal.
1845, 1855		B.M. Carew Life and Adventures.
1930		M. Fiaschetti You Gotta Be Rough 62: There’s an idea around that stool pigeons get cash. That’s mostly rot. I’ve never heard of a case where a squeal got anything like real dough from the police.

2. a complaint; a fuss.

1865		Leaves from Diary of Celebrated Burglar 139/1: The next affair was how to get the old farmer out of the house without making a squeal.
1886		Nat. Police Gaz. (NY) 17 July 14/2: One of the biggest squeals of the season is the one the managing editor of the Cincinnati Enquirer made when he was invited to appear before the [...] American Association.
1907		Sun. Times (Perth) 20 Oct. 1/1: Jack Croft’s squeal in the Senate for more post offices at Moora is humorous.
1908		N.Y. World 24 Sept. in Fleming Unforgettable Season (1981) 248: It’s a simple case of squeal. We won fair and square.
1911		S. Ford Torchy 199: Course, I don’t make any squeal at the house about my narrow escape.
1924		(con. WWI) A.G. Pretty Gloss. Sl. [...] in the A.I.F. 1921–1924 (rev. t/s) n.p.: squeal. Cry for mercy or assistance to others.
1939		W. Winchell On Broadway 5 Jan. [synd. col.] The Third Reich [...] raised a squeal that the speech was in ‘bad taste.’.
1956		‘Toney Betts’ Across the Board 80: Then there were squeals that he was fixing the races, and the stewards summoned him to stand.
1958		A. Fugard No-Good Friday (1993) 19: Oh shut up! I also got squeals. I been looking for a job for three weeks. Just let each of us keep his squeals to himself.

3. (US Und.) the report of a crime by a member of the public.

1872		G.P. Burnham Memoirs of the US Secret Service 152: This ‘squeal’ among the ‘queersmen’ brings this foul business straight home to you.
1887		G. Devol Forty Years a Gambler 13: I beat my man out of $170; and as there was no ‘squeal’ in those days, I was all right.
1901		J. Flynt World of Graft 131–2: One of the most successful bank-men this country has produced spoiled what the ‘profession’ once considered the biggest reputation of its kind in the world, by one ‘squeal’.
1914		Wash. Post 11 Nov. Misc. 3/5: [They] were the primary cause for so many ‘squeals’ from loss of leathers and blocks by the righteous.
1930		‘Leslie Charteris’ Enter the Saint 85: You think you’re going to find out [...] whether I’ve arranged for a squeal to the police.
1941		V. Davis Phenomena in Crime 74: The last mug they took on let out a squeal.
1961		J. Sparks Burglar to the Nobility 126: I was so hot they could put the squeal on me in a minute.
1977		E. Torres Q&A 71: We get a squeal that a nut-job has got a knife.
1984		J. Ellroy Blood on the Moon 153: ‘My partner and I got an unknown trouble squeal from the desk’.

4. (US und.) money that is stolen from a client of a panel crib under panel n.¹ and, when reported, is not investigated because the police have been paid off.

1876

Causes of the Increase of Crime in NY 8: [O]ne captain received [...] one-half of the ‘squeals,’ which phrase, being translated from police and thieves’ parlance into English, means the amount of money stolen in a panel-house from any individual who has complained at the station-house and who has been turned away without his complaint being prosecuted.

5. (US) a confession.

1942

W. Winchell 1 July [synd. col.] Those brave people [...] told your armed bullies to go to hell themselves when they were tortured for a squeal on who sent Heydrich to hell.

6. (US black campus) talk.

1947

M.H. Boulware Jive and Sl.

7. (US) the investigation by police of a crime, using an informer.

1953		F. Paley Rumble on the Docks (1955) 74: There were hundreds of unsolved squeals in the area.
1959		‘Ed McBain’ Killer’s Wedge (1981) 21: He’s out on a squeal, Pete. A knifing on Mason.
1981		H. Gould Fort Apache, The Bronx 81: We’re on loan to the Drug Enforcement Administration on this squeal.

8. (US police/und.) an act of informing, a tip-off to the police.

1959		W. Brown Teen-Age Mafia 7: You gotta prove you can stand up to the cops in case they latch on to you, and never let out a squeal.
1974		G. Radano Stories Cops Only Tell Each Other 133: ‘Aldo comes back. ‘Bessie was your squeal. So if you want it [i.e credit for an arrest]’ .
1986		T. Philbin Under Cover 22: It was Benton who caught the Castelli squeal.
1990		(con. early 1950s) J. Ellroy L.A. Confidential 111: No Exley – scotch a rumor he caught the Nite Owl squeal.