polish up vs perfect

polish up is not a noun while perfect is a noun.

Word	Noun	Adjective	Verb	Adverb
polish up	No	No	Yes	No
perfect	Yes	Yes	Yes	No

As verbs, perfect is a hypernym of polish up; that is, perfect is a word with a broader meaning than polish up:

Other hypernyms of polish up include hone.

polish up (noun)	perfect (noun)
	a tense of verbs used in describing action that has been completed (sometimes regarded as perfective aspect)

polish up (adjective)	perfect (adjective)
	being complete of its kind and without defect or blemish
	precisely accurate or exact
	without qualification; used informally as (often pejorative) intensifiers

polish up (verb)	perfect (verb)
bring to a highly developed, finished, or refined state	make perfect or complete