beauty sleep vs nap

beauty sleep and nap both are nouns.

Word	Noun	Adjective	Verb	Adverb
beauty sleep	Yes	No	No	No
nap	Yes	No	Yes	No

As nouns, nap is a hypernym of beauty sleep; that is, nap is a word with a broader meaning than beauty sleep:

Other hypernyms of beauty sleep include sleep.

beauty sleep (noun)	nap (noun)
sleep before midnight	sleeping for a short period of time (usually not in bed)
	a card game similar to whist; usually played for stakes
	the yarn (as in a rug or velvet or corduroy) that stands up from the weave
	a soft or fuzzy surface texture
	a period of time spent sleeping

beauty sleep (verb)	nap (verb)
	take a siesta