Definition of on a whim
- He quit his job on a whim.
: a capricious or eccentric and often sudden idea or turn of the mind : fancy
: a large capstan that is made with one or more radiating arms to which a horse may be yoked and that is used in mines for raising ore or water
What made you want to look up on a whim? Please tell us where you read or heard it (including the quote, if possible).