fast asleep

短语

熟睡的; 很快地入睡

发音

AU

释义与例句

adj.
  1. 1.

    Synonym of sound asleep.

    沉睡

    熟睡

    习语

词汇关系

形容词

同义词 1

sound asleep

近义相关 1

asleep

词源

The original sense of fast in this term is the "firmly gripped or anchored" sense, thus as if stuck fast (embedded firmly) in sleep, but the homonymy with fast as in "quickly" happens to dovetail with the fact that a very tired person will archetypally fall asleep quickly, which tends to color this term with a connotation of falling asleep both quickly and deeply.

来源：wiktionary