is a specific kind of: rest.

is a broader term that covers: bundle, practice bundling | catch a wink, catnap, nap | sleep in, sleep late | hibernate, hole up | aestivate, estivate.

is the opposite of: wake.

see also: live in, sleep in | live out, sleep out.

derivation: sleeping | sleeper, slumberer | sleep, slumber | nap, sleep | kip.