hardship vs rigor

hardship and rigor both are nouns.

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

As nouns, hardship and rigor are synonyms defined as:

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

hardship (noun)	rigor (noun)
something hard to endure	something hard to endure
something that causes or entails suffering	the quality of being valid and rigorous
a state of misfortune or affliction	excessive sternness