round vs round off

round is a noun but round off is not a noun.

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

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

Other synonyms of round include round out.

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

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

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

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

Other synonyms of round include round down, round out.

round (noun)	round off (noun)
(often plural) a series of professional calls (usually in a set order)
the usual activities in your day
the activity of playing 18 holes of golf
any circular or rotating mechanism
a charge of ammunition for a single shot
a crosspiece between the legs of a chair
a partsong in which voices follow each other; one voice starts and others join in one after another until all are singing different parts of the song at the same time
an outburst of applause
a cut of beef between the rump and the lower leg
a serving to each of a group (usually alcoholic)
a regular route for a sentry or policeman
the course along which communications spread
(sports) a division of a game during which one team is on the offensive
an interval during which a recurring sequence of events occurs

round (adjective)	round off (adjective)
having the shape or form of a circle
(of sounds) full and rich
(mathematics) expressed to the nearest integer, ten, hundred, or thousand

round (verb)	round off (verb)
become round, plump, or shapely	express as a round number
make round	make round
bring to a highly developed, finished, or refined state	bring to a highly developed, finished, or refined state
express as a round number
pronounce with rounded lips
attack in speech or writing
wind around; move along a circular course

round (adverb)	round off (adverb)
from beginning to end; throughout