WHIMSY
flightiness, arbitrariness, whimsicality, whimsy, whimsey, capriciousness
(noun) the trait of acting unpredictably and more from whim or caprice than from reason or judgment; “I despair at the flightiness and whimsicality of my memory”
notion, whim, whimsy, whimsey
(noun) an odd or fanciful or capricious idea; “the theatrical notion of disguise is associated with disaster in his stories”; “he had a whimsy about flying to the moon”; “whimsy can be humorous to someone with time to enjoy it”
Source: WordNet® 3.1
Etymology
Noun
whimsy (usually uncountable, plural whimsies)
A quaint and fanciful idea; a whim; playfully odd behaviour.
An impulsive, illogical or capricious character.
(mining) A whim (capstan or vertical drum).
A jigsaw puzzle piece that has been cut into a recognizable shape, as if on a whim; often the shape is representative of the theme of the image used for the puzzle.
Verb
whimsy (third-person singular simple present whimsies, present participle whimsying, simple past and past participle whimsied)
(transitive) To fill with whimsies or whims; to make fantastic; to craze.
To have a man's brain whimsied with his wealth.
Source: Wiktionary
Whim"sey, Whimsy, n.; pl. Whimseys or Whimsies. Etym: [See Whim.]
1. A whim; a freak; a capricious notion, a fanciful or odd conceit.
"The whimsies of poets and painters." Ray.
Men's folly, whimsies, and inconstancy. Swift.
Mistaking the whimseys of a feverish brain for the calm revelation of
truth. Bancroft.
2. (Mining)
Definition: A whim.
Whim"sy, n.
Definition: A whimsey.
Source: Webster’s Unabridged Dictionary 1913 Edition