round off vs polish up

round off and polish up both are verbs.

Word	Noun	Adjective	Verb	Adverb
round off	No	No	Yes	No
polish up	No	No	Yes	No

As verbs, round off and polish up are synonyms defined as:

round off and polish up: bring to a highly developed, finished, or refined state

Other synonyms of round off include brush up, polish, round.

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