(n.) The act or state of hibernating.

beauty sleep beddy-bye bedtime blanket drill bye-bye dormancy doze dreamland drowse fitful sleep immobility inaction inactiveness inactivity inertia land of Nod light sleep lull motionlessness quiescence repose shut-eye silken repose sleep sleepland sleepwalking slumber slumberland snoozle somnambulism somniloquy somnus suspension unconsciousness underactivity winter sleep