out cold
完全昏迷、失去知觉或晕倒
口语·形容昏迷或熟睡
英文释义
completely unconscious or deeply asleep
例句
He hit his head and was out cold for a few minutes.
典故来源
源自拳击术语，cold强调完全失去知觉的状态，类似被击倒后毫无反应。