perspicacity vs perspicaciousness

perspicacity and perspicaciousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
perspicacity	Yes	No	No	No
perspicaciousness	Yes	No	No	No

As nouns, perspicacity and perspicaciousness are synonyms defined as:

perspicacity and perspicaciousness: intelligence manifested by being astute (as in business dealings)

Other synonyms of perspicacity include astuteness, shrewdness.

perspicacity (noun)	perspicaciousness (noun)
the capacity to assess situations or circumstances shrewdly and to draw sound conclusions	intelligence manifested by being astute (as in business dealings)
intelligence manifested by being astute (as in business dealings)