frivolousness vs frivolity

frivolousness and frivolity both are nouns.

Word	Noun	Adjective	Verb	Adverb
frivolousness	Yes	No	No	No
frivolity	Yes	No	No	No

As nouns, frivolousness and frivolity are synonyms defined as:

frivolousness and frivolity: the trait of being frivolous; not serious or sensible

frivolousness (noun)	frivolity (noun)
the trait of being frivolous; not serious or sensible	acting like a clown or buffoon
	something of little value or significance
	the trait of being frivolous; not serious or sensible