Green’s Dictionary of Slang

to knock unconscious; thus cold-cocker n.; cold-cocked adj., unconscious.

1918		H. Simon ‘Prison Dict.’ in AS VIII:3 (1933) 25/2: COLDCOCK. 1, v. To knock unconscious, usually with a blackjack.
1927		(con. 1917) J. Stevens Mattock 44: Why the hell ain’t you showed some of this cold-cockin’ stuff before? [Ibid.] 231: You open up, come clean [...] or by the holy old hell you’ll get coldcocked so your mother won’t know you.
1930		D.M. Garrison ‘Song of the Pipeline’ in Botkin Folk-Say 110: Then I cold-cocks him and [...] he flops and sprawls out on the ground.
1940		W.R. Burnett High Sierra in Four Novels (1984) 415: He and another guy cold-cocked a man and clipped him for five hundred.
1953		L. Uris Battle Cry (1964) 213: You go up and coldcock him.
1960		W. Styron Set This House on Fire 438: You’d have thought Mason had been cold-cocked with a wrench.
1979		P. Hamill Deadly Piece 51: Someone got in the house and coldcocked me.
1984		W. Diehl Hooligans (2003) 404: How do we do this? We just cold-cock the son of a bitch or what?
1993		C. Hiaasen Strip Tease 127: Crandall gazed at the coldcocked candidate.
1994		N. McCall Makes Me Wanna Holler (1995) 68: Did you see that niggah’s face when I hit him? I cold-cocked his ass!
2000		S. Maloney Big Ask 49: A gutless wonder, groper of women and cold-cocker of innocent ministerial advisers.
2003		T. Dorsey Stingray Shuffle 301: Serge pulled a pistol [...] and coldcocked one over the head.
2008		G. Pelecanos Way Home (2009) 53: He was the crazy white boy who had cold-cocked a kid for no reason.
2011		‘Jack Tunney’ Split Decision [ebook] I cold-cocked a fat guy in a hat.
2018		‘Aidan Truhen’ Price You Pay 66: He will cold cock me and claim a finder’s fee.
2020		(con. 1991-94) W. Boyle City of Margins 99: ‘He had some grudge against me [...] He cold-cocked me at the bar’.