whim — OET · Shobdo

whim

noun

1 she bought it on a whim:

impulse, urge, notion, fancy, whimsy, foible, idea, caprice, conceit, vagary, kink, megrim, crotchet, craze, fad, passion, inclination, bent;

archaic freak, maggot, humour, whim-wham.

2 success depends upon something as arbitrary as human whim:

capriciousness, whimsy, caprice, volatility, fickleness, idiosyncrasy, eccentricity, unpredictability.

whim Oxford Dictionary of English