sound asleep

1. 1.

   sleeping deeply

   “lying fast asleep on the sofa”

   “it would be cruel to wake him; he's sound asleep”

   Synonymsfast asleep

   Similarasleep

Questions about sound asleep

What does sound asleep mean?

sound asleep means "sleeping deeply".

What is another word for sound asleep?

Close synonyms include fast asleep. Each sense on this page lists its own synonyms, because a word with several meanings rarely has one substitute that works for all of them.

Is sound asleep a common word?

sound asleep is banded "Rare" — specialist or archaic — most readers will not have met it. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.