whimsy vs flightiness

whimsy and flightiness both are nouns.

Word	Noun	Adjective	Verb	Adverb
whimsy	Yes	No	No	No
flightiness	Yes	No	No	No

As nouns, whimsy and flightiness are synonyms defined as:

whimsy and flightiness: the trait of acting unpredictably and more from whim or caprice than from reason or judgment

Other synonyms of whimsy include arbitrariness, capriciousness, whimsey, whimsicality.

whimsy (noun)	flightiness (noun)
the trait of acting unpredictably and more from whim or caprice than from reason or judgment	the trait of acting unpredictably and more from whim or caprice than from reason or judgment
an odd or fanciful or capricious idea