rigorousness vs inclemency

rigorousness and inclemency both are nouns.

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

As nouns, rigorousness and inclemency are synonyms defined as:

Other synonyms of rigorousness include hardness, harshness, rigor, rigour, rigourousness, severeness, severity, stiffness.

rigorousness (noun)	inclemency (noun)
something hard to endure	excessive sternness
excessive sternness	weather unsuitable for outdoor activities