KO
verb [ T ] informal uk/ˌkeɪˈəʊ/ us/ˌkeɪˈoʊ/ KO'ing | KO'd
（尤指拳击中）击倒（对手）
to make someone unconscious, especially in boxing
使某人极度虚弱、劳累或生病
to make someone feel very weak, tired, and ill
That flu really KO'd me for a while. 流感着实把我打到了一阵子。