Synonyms for Slumber:

n.

drift off, drop off, snooze, go off, doze off, go to sleep, drowse. be in the land of Nod, catch some shuteye, sleep tight, awareness. doze (noun)
forty winks, drowse.
inactivity (noun)
rest.
sleep (noun)
beauty sleep, doze, forty winks, drowse, rem sleep, snooze, rest, dreamland, power nap, the land of Nod, catnap.
slumber (noun)
kip, log z's, sleep, catch some z's.

v.

rest (verb)
still, mark time, pause, quiet, subside, stand, rest, stay, tranquilize, sleep, vegetate, settle down, fix, calm, settle, wait, stagnate, becalm.

Other synonyms:

dreamland. doze
drift off.
log Z's
log z's.
nap
doze.
repose
settle down.
Other relevant words:
catnap, sleep tight, log z's, catch some shuteye, forty winks, dreamland, go to sleep, beauty sleep, kip, snooze, doze, drowse, doze off, catch some z's, be in the land of Nod.

Usage examples for slumber

  1. At daylight we all fell into a feverish slumber which lasted several hours. – New National Fourth Reader by Charles J. Barnes and J. Marshall Hawkes
  2. She awoke from slumber – The Flying Legion by George Allan England
  3. He was never sure at what point he drifted off into deep slumber – The Flying Stingaree by Harold Leland Goodwin