individualise vs separate

individualise is not a noun while separate is a noun.

Word	Noun	Adjective	Verb	Adverb
individualise	No	No	Yes	No
separate	Yes	Yes	Yes	No

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

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

individualise (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

individualise (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

individualise (verb)	separate (verb)
make personal or more personal	become separated into pieces or fragments
make or mark or treat as individual	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