severeness vs hardship

severeness and hardship both are nouns.

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

As nouns, severeness and hardship are synonyms defined as:

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

severeness (noun)	hardship (noun)
extreme plainness	something hard to endure
excessive sternness	something that causes or entails suffering
something hard to endure	a state of misfortune or affliction
used of the degree of something undesirable e.g. pain or weather