CAPRICIOUS

adj. whimsical, erratic, flighty, fickle, mercurial, unsteady, variable, unstable, wayward, unpredictable, undependable, changeable, impulsive, crotchety, quirky, unreliable, inconstant, fanciful, wanton His decisions are capricious and not based on sound judgement The weather in March is capricious as Mark Twain said, if you don't like it, just wait five minutes