capricious adjective: governed or characterized by caprice : impulsive, unpredictable
The court ruled that the punishmentwas arbitrary and capricious.
“Some of her songs are humorous, even capricious, though many reflecton the more hidden of life‘s injustices.” — St. Augustine (Florida) Record, February 27, 2015
Did you know?
The noun caprice, which firstappeared in English in the mid-17thcentury, is a synonym of whim. Evidence shows that the adjectivecapricious debuted about sixty yearsbefore caprice; it’s likely, however, that both words derived via Frenchfrom the Italian capriccio, whichoriginally referred not to a suddendesire but to a sudden shudder of fear. Capriccio in turn derives fromthe Italian capo, meaning “head,” and riccio, the word for “hedgehog.” Someone who shuddered in fear, therefore, was said to have a “hedgehog head“—meaning that his or her hair stood on end like the spines of a hedgehog.