asperity vs rigorousness

asperity and rigorousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
asperity	Yes	No	No	No
rigorousness	Yes	No	No	No

As nouns, asperity and rigorousness are synonyms defined as:

Other synonyms of asperity include grimness, hardship, rigor, rigour, rigourousness, severeness, severity.

asperity (noun)	rigorousness (noun)
something hard to endure	something hard to endure
harshness of manner	excessive sternness