An odd or fanciful or capricious idea. Synonyms:notion, whim, whimsey."He had a whimsy about flying to the moon" , "Whimsy can be humorous to someone with time to enjoy it"
... the department could endeavor now to do was to restrict the conflagration's lateral spread, to keep the daemon in the track he had chosen, and not allow him to stray to east or west. But they reckoned without his whimsy. ... — White Ashes • Sidney R. Kennedy and Alden C. Noble
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