K.O. (acronym) Type: noun, acronym, slang Pronunciation: /k-o/ Also spelled: KO, K.O What does K.O. mean and stand for? Knock Out. K.O. Synonyms: Sleep him Example sentence: “The fight ended with a K.O.“ K.O. in songs: “Catch him in the club, K.O.” – King Louie, Faneto (Remix). “I might just K.O., the Perc’ up in […]