hardship vs rigorousness

hardship and rigorousness both are nouns.

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

As nouns, hardship and rigorousness are synonyms defined as:

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

hardship (noun)	rigorousness (noun)
something hard to endure	something hard to endure
something that causes or entails suffering	excessive sternness
a state of misfortune or affliction