heterology vs unsimilarity

heterology and unsimilarity both are nouns.

Word	Noun	Adjective	Verb	Adverb
heterology	Yes	No	No	No
unsimilarity	Yes	No	No	No

As nouns, unsimilarity is a hypernym of heterology; that is, unsimilarity is a word with a broader meaning than heterology:

heterology: (biology) the lack of correspondence of apparently similar body parts
unsimilarity: the quality of being dissimilar

Other hypernyms of heterology include dissimilarity.

heterology (noun)	unsimilarity (noun)
(biology) the lack of correspondence of apparently similar body parts	the quality of being dissimilar