perspicuity vs perspicuousness

perspicuity and perspicuousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
perspicuity	Yes	No	No	No
perspicuousness	Yes	No	No	No

As nouns, perspicuity and perspicuousness are synonyms defined as:

perspicuity and perspicuousness: clarity as a consequence of being perspicuous

Other synonyms of perspicuity include plainness.

perspicuity (noun)	perspicuousness (noun)
clarity as a consequence of being perspicuous	clarity as a consequence of being perspicuous