Whim

Noun

 * 1) A fanciful impulse, or whimsical idea
 * 2)  A large capstan or vertical drum turned by horse power or steam power, for raising ore or water, etc., from mines, or for other purposes

Synonyms

 * lark, especially in phrase on a lark

Thesaurus
apparition, bee, boutade, brainchild, brainstorm, bubble, capriccio, caprice, chimera, conceit, crank, craze, crazy idea, crotchet, delirium, disposition, dream, eidolon, fad, fancy, fantasque, fantastic notion, fantasy, fiction, figment, flimflam, fool notion, freak, freakish inspiration, hallucination, harebrained idea, humor, idea, idle fancy, illusion, imagery, imagination, imagining, inclination, insubstantial image, invention, kink, maggot, make-believe, megrim, myth, notion, passing fancy, phantasm, phantom, quirk, romance, sick fancy, thick-coming fancies, thought, toy, trip, vagary, vapor, vision, whim-wham, whimsy, wildest dreams