Wiktionary
a. (context idiomatic English) Sleeping, in a deep sleep
WordNet
adj. sleeping deeply; "lying fast asleep on the sofa"; "it would be cruel to wake him; he's sound asleep" [syn: fast asleep(p), sound asleep(p)]
Usage examples of "fast asleep".
After relieving himself, Viztria had gone back into his sleeping chamber and stripped off his clothes quicker than a fifteen-year-old nobleman's daughter from Rillanon could shuck her first ballgown in the back seat of a closed carriage, and was fast asleep before his head hit the pillow, and if there were no further insulting questions, he would just as soon let the Captain get on to insulting somebody else.
And then, somewhere along, the drug is so gentle and he's so fast asleep that he never notices when, he dies.
The next thing I knew, he'd just folded up in a heap on the ground, fast asleep.
He now prepared to leave, and I started for my own room, and was soon fast asleep.
He gestured toward the small brown cat, fast asleep in a cat-basket in the corner of the room.
Sharra was peering at Ruth, who was still fast asleep, not even an eyelid twitching.
By the time the frame had been completed, Master Wansor was fast asleep, his head cushioned on his hands, snoring in a soft rhythm.
Sammy lay fast asleep amid his tousled blankets, his face illuminated by a quadrant of streetlight from the highway.
Ned, Gendry, and many of the others were fast asleep when Arya spied the small pale shape creeping behind the horses, thin white hair flying wild as she leaned upon a gnarled cane.