tarnish vs sully

tarnish is a noun but sully is not a noun.

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

As verbs, tarnish and sully are synonyms defined as:

tarnish and sully: make dirty or spotty, as by exposure to air; also used metaphorically

Other synonyms of tarnish include defile, maculate, stain.

tarnish (noun)	sully (noun)
discoloration of metal surface caused by oxidation

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