noun
caprice refers to a sudden, impulsive, apparently unmotivated turn of mind or emotion discharged at the caprice of a foreman; whim and whimsy can both refer to an idle, quaint, or curious notion, but whim more often suggests willfulness and whimsy fancifulness pursuing a whim, he wrote a poem full of whimsy; vagary suggests a highly unusual or extravagant notion the vagaries of fashion in women's clothes; crotchet implies great eccentricity and connotes stubbornness in opposition to prevailing thought, usually on some insignificant point his crotchets concerning diet
See caprice in Webster's New World Roget's A-Z Thesaurus II
Learn more about caprice