1. (noun)flightiness, arbitrariness, whimsicality, whimsy, whimsey, capriciousness 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"
2. (noun)impishness, mischievousness, puckishness, whimsicality the trait of behaving like an imp