somewhat vs pretty

somewhat is not an adjective while pretty is an adjective.

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

As adverbs, somewhat and pretty are synonyms defined as:

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

somewhat (adjective)	pretty (adjective)
	(used ironically) unexpectedly bad
	pleasing by delicacy or grace; not imposing

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