ipsedixitism vs asseveration

ipsedixitism and asseveration both are nouns.

Word	Noun	Adjective	Verb	Adverb
ipsedixitism	Yes	No	No	No
asseveration	Yes	No	No	No

As nouns, asseveration is a hypernym of ipsedixitism; that is, asseveration is a word with a broader meaning than ipsedixitism:

ipsedixitism: an unsupported dogmatic assertion
asseveration: a declaration that is made emphatically (as if no supporting evidence were necessary)

Other hypernyms of ipsedixitism include assertion, averment.

ipsedixitism (noun)	asseveration (noun)
an unsupported dogmatic assertion	a declaration that is made emphatically (as if no supporting evidence were necessary)