inapplicability vs irrelevancy

inapplicability and irrelevancy both are nouns.

Word	Noun	Adjective	Verb	Adverb
inapplicability	Yes	No	No	No
irrelevancy	Yes	No	No	No

As nouns, irrelevancy is a hypernym of inapplicability; that is, irrelevancy is a word with a broader meaning than inapplicability:

inapplicability: irrelevance by virtue of being inapplicable to the matter at hand
irrelevancy: the lack of a relation of something to the matter at hand

Other hypernyms of inapplicability include irrelevance.

inapplicability (noun)	irrelevancy (noun)
irrelevance by virtue of being inapplicable to the matter at hand	the lack of a relation of something to the matter at hand