darken vs sully

darken and sully both are verbs.

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

As verbs, sully is a hypernym of darken; that is, sully is a word with a broader meaning than darken:

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

Other hypernyms of darken include defile, maculate, stain, tarnish.

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