n. 1. A sudden or capricious idea; a fancy: “More than five hundred of these men would never see another sunset, yet a holiday atmosphere prevailed; they joked with each other as they marched, dropping out again for blackberries when the whim struck them, despite stern new orders to the contrary” (William Marvel).
2. Arbitrary thought or impulse: “I dreamed of having the golden flesh, the huge muscles of half-naked gods and goddesses who did whatever they wanted to do, ruling the universe according to their whims” (John Edgar Wideman).
3. A vertical horse-powered drum used as a hoist in a mine.
on a whim Done suddenly or impulsively: “I just took a trip. Lit off at night, drove six hundred miles to see an old friend, on a whim” (Marya Hornbacher).