slightly vs somewhat

slightly and somewhat both are adverbs.

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

As adverbs, slightly and somewhat are synonyms defined as:

Other synonyms of slightly include more or less.

slightly (adverb)	somewhat (adverb)
to a small degree or extent	to certain extent or degree
in a slim or slender manner	to a small degree or extent