fast asleep
Speech parts
1. fast asleep - Adjective
2. fast asleep - Adjective Satellite
Meaning
sleeping deeply
Source: WordNetSynonyms
Antonyms
Examples
lying fast asleep on the sofa
it would be cruel to wake him; he's sound asleep
However, if you're planning on using the system as a way of making sure they're not staying up late reading or playing video games, forget it – all they have to do is take off the band and the Fitbit app assumes they're fast asleep.
Mama would be more difficult, but she took so many sleeping pills, she’d be fast asleep, steeped in her jasmine and geranium essences.
So I kick up my feet, have a snack, and vow to stay up late catching up on a book I've been trying to finish or a show I'm behind on, but four seconds later I'm fast asleep, remote in hand.
By the time my husband arrived, my daughter was fast asleep, and I was feeling more hopeful.