whim

whim — noun

1. A sudden thought or desire, often without a clear reason, that makes a person ac

1.nounB2
Definition

A sudden thought or desire, often without a clear reason, that makes a person act on impulse rather than through careful planning.

Example

On a whim, Rodrigo booked a flight to Tokyo after seeing photos of the cherry blossoms.

on a whim (adverbial phrase for acting impulsively)

The team's entire schedule changed at their manager's whim, leaving everyone frustrated.

at the whim of [someone] (phrase for unpredictable authority)

Common collocations
  • on a whim
  • at the whim of
  • sudden whim
  • mere whim
  • passing whim
  • act on a whim
Synonyms
  • impulse

    Stronger and more urgent; an impulse usually leads to immediate action, while a whim can remain a passing thought.

  • fancy

    Lighter and more playful; a fancy is based on liking something, whereas a whim is more unpredictable and less rational.

  • caprice

    More formal and literary; caprice emphasises sudden, unmotivated changes of mind, often in contexts of power or authority.

  • notion

    Broader — a notion can be a well-considered idea, while a whim is always sudden and impulsive.

Antonyms
  • plan

    A plan is carefully thought through; a whim arises without forethought.

  • intention

    An intention implies deliberate purpose; a whim lacks commitment and reason.

Grammar Patterns

on a whim (acts as an adverbial phrase)

at the whim of [someone/something]

[adjective] + whim (sudden / mere / passing)

Usage Note

Common in the fixed phrases 'on a whim' (meaning impulsively or without planning) and 'at the whim of [someone/something]' (meaning subject to unpredictable decisions). The noun is frequently modified by 'sudden', 'passing', or 'mere' to indicate how serious or lasting the impulse is.

Common Mistakes

I bought the coat by whim.
I bought the coat on a whim.
The correct preposition is 'on', not 'by'.
He had a whim.
He had a sudden whim to learn French.
'Whim' alone sounds incomplete; it usually needs a modifier or a following infinitive to feel natural.

Word family

  • whimsical
    adjectiveB2
  • whimsy
    nounC1
  • whim-wham
    noun

Synonym discussion

Sense: noun/1

All five words describe thoughts or desires, but they differ in urgency and rationality. 'Whim' suggests a sudden, often inexplicable desire to do something unusual — it may or may not lead to action. 'Impulse' is stronger: it carries an urgency that pushes someone to act immediately, often without any reflection. 'Fancy' is lighter and more pleasant; it is a gentle liking or imagination rather than a driving urge. 'Caprice' is the most formal and implies an arbitrary change of mind, often exercised by someone in a position of power over others. 'Notion' is the broadest — it can be a general idea or belief, whereas the other three all imply suddenness or lack of reason. For example, deciding 'on a whim' to learn the flute is different from feeling an 'impulse' to catch a falling vase. A 'fancy' for vintage hats is a mild preference, not a sudden urge; a manager who changes rules by 'caprice' does so unpredictably; and a 'notion' about health might be a long-held belief, not a passing thought.

whim ↗impulse ↗fancy ↗capricenotion ↗

Common collocations

Phrases

  • on a whim
  • at the whim of
  • act on a whim
  • change according to whim

Prepositions

  • on a whim
  • at the whim of

Etymology

English

'Whim' is a shortened form of the 16th-century word 'whim-wham', a playful reduplication that originally referred to a decorative trinket or fanciful object. By the late 1600s, the meaning had shifted from the object itself to the fanciful, unpredictable state of mind that produces such ideas — the modern sense of a sudden or capricious impulse.