jolly vs somewhat

jolly is a noun but somewhat is not a noun.

Word	Noun	Adjective	Verb	Adverb
jolly	Yes	Yes	Yes	Yes
somewhat	No	No	No	Yes

As adverbs, jolly and somewhat are synonyms defined as:

Other synonyms of jolly include fairly, middling, moderately, passably, pretty, reasonably.

jolly (noun)	somewhat (noun)
a yawl used by a ship's sailors for general work
a happy party

jolly (adjective)	somewhat (adjective)
full of or showing high-spirited merriment

jolly (verb)	somewhat (verb)
be silly or tease one another

jolly (adverb)	somewhat (adverb)
to certain extent or degree	to certain extent or degree
	to a small degree or extent