half-wit vs dimwit

half-wit and dimwit both are nouns.

Word	Noun	Adjective	Verb	Adverb
half-wit	Yes	No	No	No
dimwit	Yes	No	No	No

As nouns, half-wit and dimwit are synonyms defined as:

Other synonyms of half-wit include doofus, nitwit.

half-wit (noun)	dimwit (noun)
a stupid incompetent person	a stupid incompetent person
a person of subnormal intelligence