impair vs sully

impair and sully both are verbs.

Word	Noun	Adjective	Verb	Adverb
impair	No	No	Yes	No
sully	No	No	Yes	No

As verbs, sully is a hyponym of impair; that is, sully is a word with a more specific, narrower meaning than impair:

Other hyponyms of impair include cloud, corrupt, defile, taint, blemish, deface, disfigure.

impair (verb)	sully (verb)
make worse or less effective	charge falsely or with malicious intent; attack the good name and reputation of someone
make imperfect	make dirty or spotty, as by exposure to air; also used metaphorically
	place under suspicion or cast doubt upon