disaffirmation vs averment

disaffirmation and averment both are nouns.

Word	Noun	Adjective	Verb	Adverb
disaffirmation	Yes	No	No	No
averment	Yes	No	No	No

As nouns, averment is a hypernym of disaffirmation; that is, averment is a word with a broader meaning than disaffirmation:

disaffirmation: the act of asserting that something alleged is not true
averment: a declaration that is made emphatically (as if no supporting evidence were necessary)

Other hypernyms of disaffirmation include assertion, asseveration.

disaffirmation (noun)	averment (noun)
the act of asserting that something alleged is not true	a declaration that is made emphatically (as if no supporting evidence were necessary)