round off vs perfect

round off is not a noun while perfect is a noun.

Word	Noun	Adjective	Verb	Adverb
round off	No	No	Yes	No
perfect	Yes	Yes	Yes	No

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

Other hypernyms of round off include hone.

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

round off (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

round off (verb)	perfect (verb)
express as a round number	make perfect or complete
make round
bring to a highly developed, finished, or refined state