absurdity vs absurdness

absurdity and absurdness both are nouns.

Word	Noun	Adjective	Verb	Adverb
absurdity	Yes	No	No	No
absurdness	Yes	No	No	No

As nouns, absurdity and absurdness are synonyms defined as:

absurdity and absurdness: a message whose content is at variance with reason

Other synonyms of absurdity include ridiculousness.

absurdity (noun)	absurdness (noun)
a ludicrous folly	a message whose content is at variance with reason
a message whose content is at variance with reason