Learner's definition of ASLEEP
not used before a noun
1 : in a state of sleep : sleeping
“Are you asleep?” “No, I'm awake.”
He tries to clean up the house while the kids are asleep.
The cats are asleep on the floor.
She was still asleep at noon.
◊ When people are fast asleep or sound asleep, they are sleeping very deeply.
It was late at night and everyone was fast asleep.
One moment she was sound asleep, the next she was wide awake!
If you are half asleep, you are very tired and not completely awake.
2 : lacking any feeling
◊ If a part of your body (such as a foot or leg) is asleep, it is not able to feel anything for a brief time, usually because you have kept it in an awkward position for too long.