whimsey vs flightiness

whimsey and flightiness both are nouns.

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

As nouns, whimsey and flightiness are synonyms defined as:

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

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

whimsey (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