capricious

/kə-ˈpri-shəs/

borrowed from Middle French capricieux, borrowed from Italian capriccioso, from capriccio caprice-oso -ous

adjective

  1. governed or characterized by caprice : impulsive, unpredictable

inconstant fickle capricious mercurial unstable mean lacking firmness or steadiness (as in purpose or devotion). inconstant implies an incapacity for steadiness and an inherent tendency to change. fickle suggests unreliability because of perverse changeability and incapacity for steadfastness.