Green’s Dictionary of Slang

to knock out, lit. or fig.

1905		C. Chesnutt Colonel’s Dream 28: So when I got my laig kyo’ed up [...] I come back hyuh whar I wuz bo’n.
1924		E. Hemingway letter 6 Dec. in Baker Sel. Letters (1981) 136: You coud have KO’ed me with the proverbial pinion.
1927		A. Johnston Ten-and-out! 156: After his losing fight against the champion, Sharkey rested [...] then got back into the ring again. He thrashed and kayoed Goddard.
1930		M. West Babe Gordon (1934) 75: Bearcat’s manager K.O.’s romance for the big Bearcat.
1937		J. Curtis There Ain’t No Justice 39: I kayoed him easy.
1941		‘Digg Mee’ ‘Observation Post’ in N.Y. Age 15 Nov. 9/5: He in turn was k.o.’d, floored.
1945		Sun (Sydney) 12 Aug. 8/3: Once he kayoed her in the street.
1947		D. Davin For the Rest of Our Lives 333: 75 tanks KO’d.
1947		B. Schulberg Harder They Fall (1971) 174: One of the guys he kayoed [...] damn near died.
1950		Illus. 30 Dec. 28: We lose our only world title when Freddie Mills is k.o’d by [Joey] Maxim.
1957		H. Simmons Corner Boy 199: You were kayoed when the opening bell went off.
1961		T. Murphy Whistle in the Dark Act I: And Hugo struck and then, / Upon the floor, all K.O. dead, / Were the bloody Englishmen!
1962		Ragen & Finston World’s Toughest Prison 806: kayoe – To achieve unusual success.
1967–8		C. Bukowski Notes of a Dirty Old Man (1973) 47: Watson was kayoed which made it a very bitter night.
1973		Batman No. 251 10: The idiot – I’m the only thing between him and a coffin, and he kayoes me!
1974		J. Lahr Hot to Trot 193: A bee sting has swollen [...] my lip. I’m as puffed and hideous as a KO’d fighter.
1983		J. Byrell (con. 1959) Up the Cross 75: Brucie the Rooster duly kayoed his cheese, Maureen, by suggesting [...] ‘a romantic little boat trip’.
1988		S. King Tommyknockers (1989) 123: The huge brainless grin of a KO’d fighter just before his knees come unhinged.
1990		S. Morgan Homeboy 97: Quick Cicero’s heart and soul were kayoed.
1992		M. Leyner Et Tu, Babe (1993) 23: No matter how many pugs he KO’d in the ring [...] there was always a beautiful woman struggling to emerge.
1996		J. Byrell Lairs, Urgers & Coat-Tuggers 130: The Darb nearly got kayoed by that lemonade bottle.
2005		J. Stahl I, Fatty 265: Maybe I was the only man in America secretly glad when the market got kayoed.