Sound asleep is a phrase used to describe a state of deep sleep. It is often associated with snoring, which is the sound made when someone is sleeping deeply. The crossword solutions for the term sound asleep are SNORE (5 letters), OUT (3 letters), and ZZZ (3 letters). SNORE is the sound made when someone is sleeping deeply, OUT is a term used to describe the end of something, and ZZZ is an onomatopoeia used to represent the sound of snoring.