severity vs asperity

severity and asperity both are nouns.

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

As nouns, severity and asperity are synonyms defined as:

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

severity (noun)	asperity (noun)
excessive sternness	something hard to endure
used of the degree of something undesirable e.g. pain or weather	harshness of manner
something hard to endure
extreme plainness