sleep

bed, catnapping, dozing, napping, repose, rest, resting, shut-eye, slumber, slumbering, snoozing, z's (or zs)

dead, deadness, death, grave, lifelessness, nothingness

curtains, death, decease, demise, dissolution, doom, end, exit, expiration, fate, grave, great divide, passage, passing, quietus

catnap, doze, nap, rest, slumber, snooze

breed, copulate, mate