darken vs defile

darken is not a noun while defile is a noun.

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

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

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

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

darken (noun)	defile (noun)
	a narrow pass (especially one between mountains)

darken (verb)	defile (verb)
become dark or darker	spot, stain, or pollute
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