Green’s Dictionary of Slang

1. (orig. US) to die; too kill oneself.

1929		Hostetter & Beesley It’s a Racket! 222: check out — Leave hastily; also, die a natural death.
1934		A. Halper Foundry 55: At the sound of a sharp cracking noise you will know that I have finally checked out!
1940		S. Sterling ‘Ten Carats of Lead’ in Black Mask Stories (2010) 220: Guy gets toughened up after twenty years on a beat. Makes it that much harder to check out.
1946		Mezzrow & Wolfe Really the Blues 16: I landed in the hospital with dysentery and I almost checked out.
1950		Goldin et al. DAUL 42/2: Check out. (P) To leave prison by any means: death, escape, parole, discharge, court order, or transfer to another prison.
a.1964		‘Bad Dan’ in D. Wepman et al. Life (1976) 126: Tell them Billy Clapshit just checked out.
1977		(con. 1949) J.G. Dunne True Confessions (1979) 105: Second time in six months a guy checked out in this fleabag, he was in the saddle.
1993		I. Welsh Trainspotting 37: This was Andy’s third heart attack and now [...] he had finally checked out.
2000		Indep. Rev. 11 Feb. 10: He checks out permanently by slashing his wrists.
2006		D. Winslow Winter of Frankie Machine (2007) 55: Whether he’s looking at the white light, or whatever, he’s already checked out of this motel.
2017		T. Pluck Bad Boy Boogie [ebook] ‘If he checked out from the guilt, he dug his own grave far as I’m concerned’.

2. (orig. US) to leave.

1929		H.C. Witwer Yes Man’s Land 6: I’m checking out of New York.
1933		J.T. Farrell Gas-House McGinty 68: I want to see places [...] and after I get that back pay, I’m checkin’ out.
1953		R. Chandler Long Good-Bye 59: ‘Terry Lennox shot himself this afternoon. So they say. So they say.’ [...] But there ain’t going to be no trial. On account of Lennox checked out before it could get moving.
1958		H. Ellison Web of the City (1983) 24: Nobody checks out on the gang, y’unnerstand?
1966		M. Rumaker Exit 3 and Other Stories 8: C’mon, soldier, this is where you check out.
1976		A. Salkey Come Home, Malcolm Heartland 187: I should a check out when I was born, or don’t born there, at all.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 641: She said Pete checked out — ‘Against doctor’s advice’.

3. to kill.

1976

R. Price Blood Brothers 119: If I ever got like that, and I asked you to check me out, would you do me the solid?

4. to give up, to leave in fig. sense.

2012		R.A. Dickey Wherever I Wind Up 19: [H]e went from being a dad who would do everything with his son to a dad who more or less checked out.
2021		P. Papathanasiou Stoning 258: ‘Yair, we know the bastard checked out a while ago. Can’t blame him, really’.