irony vs incongruousness

irony and incongruousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
irony	Yes	No	No	No
incongruousness	Yes	No	No	No

As nouns, incongruousness is a hypernym of irony; that is, incongruousness is a word with a broader meaning than irony:

irony: incongruity between what might be expected and what actually occurs
incongruousness: the quality of disagreeing; being unsuitable and inappropriate

Other hypernyms of irony include incongruity.

irony (noun)	incongruousness (noun)
incongruity between what might be expected and what actually occurs	the quality of disagreeing; being unsuitable and inappropriate
a trope that involves incongruity between what is expected and what occurs
witty language used to convey insults or scorn