inclemency vs severity

inclemency and severity both are nouns.

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

As nouns, inclemency and severity are synonyms defined as:

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

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