grimness vs hardship

grimness and hardship both are nouns.

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

As nouns, grimness and hardship are synonyms defined as:

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

grimness (noun)	hardship (noun)
something hard to endure	something hard to endure
the quality of being ghastly	something that causes or entails suffering
	a state of misfortune or affliction