severeness vs inclemency

severeness and inclemency both are nouns.

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

As nouns, severeness and inclemency are synonyms defined as:

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

severeness (noun)	inclemency (noun)
extreme plainness	excessive sternness
excessive sternness	weather unsuitable for outdoor activities
something hard to endure
used of the degree of something undesirable e.g. pain or weather