severity vs inclemency

severity and inclemency both are nouns.

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

As nouns, severity and inclemency are synonyms defined as:

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

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