The Open Dictionary

KO

verb

UK/ˌkeɪˈəʊ/
US/ˌkeɪˈoʊ/

Definitions of KO verb

  1. Transitive

    To render someone unconscious, especially in boxing or combat sports.

    • The boxer knocked his opponent out with a right hook.

    • He was KO'd in the final round of the match.

    • His coach told him that he needed to figure out how to KO his opponent.

  2. Transitive

    To cause someone to feel extremely weak, fatigued, or unwell; to exhaust or incapacitate.

    • The consecutive days of meetings and travel really KO'd me.

    • That illness completely KO'd me; I need time to recover.

    • The long hours at work totally KO'd him.