countervail vs cancel

countervail is not a noun while cancel is a noun.

Word	Noun	Adjective	Verb	Adverb
countervail	No	No	Yes	No
cancel	Yes	No	Yes	No

As verbs, cancel is a hypernym of countervail; that is, cancel is a word with a broader meaning than countervail:

Other hypernyms of countervail include offset, set off.

countervail (noun)	cancel (noun)
	a notation cancelling a previous sharp or flat

countervail (verb)	cancel (verb)
oppose and mitigate the effects of by contrary actions	make invalid for use
compensate for or counterbalance	remove or make invisible
	declare null and void; make ineffective
	postpone indefinitely or annul something that was scheduled
	make up for