Green’s Dictionary of Slang

1. (US Und., also cop out on) to confess, to inform.

1931		L. Britton Hunger & Love 65: If anybody had thought to come along and ask you, you'd have copped out.
1943		D. Burley N.Y. Amsterdam News 23 Oct. 21: We were done like a picture and had to cop out.
1953		T. Runyon In For Life 129: I guess I’ll have to cop out.
1967		M. Braly On the Yard (2002) 239: Though both Chilly and Caterpillar refused to cop out, they were routinely convicted through Raquel’s testimony.
1967		L. Bruce Essential Lenny Bruce 215: Oh, oh, somebody copped out on him.
1968		‘Sl. of Watts’ in Current Sl. III:2 18: Cop, v. To admit something.
1971		T. Thackrey Thief 404: Better cop-out to me before my partner gets back.
1980		E. Folb Runnin’ Down Some Lines 36: The highest mark of a real partner was that the person didn’t [...] cop out, or drop a dime by informing.
1981		E. Bunker Little Boy Blue (1995) 165: He copped out that he started it [i.e. a fight].
1990		S. Morgan Homeboy 132: He would plead not guilty but be ready to cop out if their case was airtight.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 603: She said you’re going back — I know it. He copped out. He said let me go.
2010		J. Ellroy Hilliker Curse 4: My father copped out to peeping [...] to indict my mother’s indigenous moral sloth.

2. (US Und.) to use legal plea-bargaining to plead guilty to a lesser charge in return for having one dropped.

1938		Flynn’s 23 Apr. n.p.: It was a bum beef but I copped out for a deuce because I was hot on a jug heist that called for a double sawbuck [DU].
1951		J. Blake letter 25 Feb. in Joint (1972) 13: I copped out on the larceny charges, figuring to get six months at the most.
1961		M. Braly Felony Tank (1962) 48: They probably thought you were going to cop out to every job pulled in this country in the last fifteen years.
1977		B. Jackson Killing Time 177: I think the charge was grand larceny. I copped out for one year anyway.
1985		N. Pileggi Wiseguy (2001) 26: Cop-out Louie copped me out to an ‘attempted’ petty larceny and I got a six-month suspended sentence.
1994		P. Baker Blood Posse 258: Weatherman [...] started introducing me to the idea of copping out and getting a lenient sentence.

3. to avoid a problem or a difficult situation, to run away, to give up trying.

1949		N. Algren Man with the Golden Arm 266: You’re gonna cop out for this deal tonight.
1958		E. Gilbert Vice Trap 56: You think you’ll be rich off him? Cop out, man: he look like Santa Claus to you?
1959		‘Paul Merchant’ ‘Sex Gang’ in Pulling a Train’ (2012) [ebook] So you’re gonna cop out on me, huh [...] Like hell you are.
1966		H.S. Thompson letter 28 June in Proud Highway (1997) 576: He copped out and said I should write the letter.
1977		C. McFadden Serial 45: The least he could do after copping out on Marlene [...] was to get in touch with her again.
1980		Observer Mag. 24 Feb. 33: I wouldn’t like to have them say: ‘You copped out’, he confesses.
1986		C. Bowles G’DAY 94: Yer not gunna cop out now. Come on — we’re late.
1994		N. McCall Makes Me Wanna Holler (1995) 333: I thought they were copping out because they were scared to compete.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 46/1: cop out v. to back down or withdraw.

4. (US black/jazz) to go to sleep.

1959

Esquire Nov. 70I: cop out: go to sleep. Evasiveness. Excuse.

5. (also cop out on) to let down, to betray.

1965		L. Bruce How to Talk Dirty 57: This is not copping out on the ‘starving masses of India and China’.
1970		G. Scott-Heron Vulture (1996) 27: All it [i.e. good manners] really turns out to be iz coppin’ out on yo’ manhood.

6. (US black/gang) to leave the gang.

1969

R.L. Keiser Vice Lords 67: [P]eople thought we had actually cut ourselves loose from the group. I guess they thought we was going to cop out.