know apart vs separate

know apart is not a noun while separate is a noun.

Word	Noun	Adjective	Verb	Adverb
know apart	No	No	Yes	No
separate	Yes	Yes	Yes	No

As verbs, separate is a hypernym of know apart; that is, separate is a word with a broader meaning than know apart:

Other hypernyms of know apart include differentiate, distinguish, secern, secernate, severalise, severalize, tell, tell apart.

know apart (noun)	separate (noun)
	a garment that can be purchased separately and worn in combinations with other garments
	a separately printed article that originally appeared in a larger publication

know apart (adjective)	separate (adjective)
	independent; not united or joint
	standing apart; not attached to or supported by anything
	separated according to race, sex, class, or religion
	have the connection undone; having become separate

know apart (verb)	separate (verb)
recognize or perceive the difference	become separated into pieces or fragments
	divide into two or more branches so as to form a fork
	arrange or order by classes or categories
	mark as different
	move or break apart
	force, take, or pull apart
	divide into components or constituents
	go one's own way; move apart
	make a division or separation
	treat differently on the basis of sex or race
	separate into parts or portions
	discontinue an association or relation; go different ways
	act as a barrier between; stand between