Whimsy. /ˈwɪmzi/ synonyms: arbitrariness, capriciousness, flightiness, whimsey, whimsicality. type of: irresponsibility, irresponsibleness. Damn. That doesn't sound so good. Good thing the thesaurus doesn't have much of a role in modern society. Especially not in the Rank Ideas HQ, which doesn't even have a bookshelf. Purple monkey dishwasher.