whim

Compared meaning: a sudden wish to do something, without thinking (noun).

比较义项：未经理性思考、突然产生的想做某事的念头（名词）。

• impulse

  Suggests a strong, often hard-to-resist urge to act suddenly; used in the fixed phrase 'on impulse' (no article) and can describe fairly serious or emotional actions.

  指强烈、往往难以抗拒的、想要突然行动的冲动；常用于固定短语“on impulse”（不加冠词），可用来描述较严重或情绪化的行为。

  She bought the shoes on impulse without really thinking about it.

  她一时冲动买下了那双鞋，并没有认真考虑。

• whim 本词

  Suggests a lighter, more frivolous or playful sudden idea, often trivial and not based on any real reason; used with an article, as in 'a whim' or 'on a whim'.

  指较轻松、随性甚至没有明确理由的一时念头，通常显得轻率或不太认真；常带冠词，构成“a whim”或“on a whim”。

  On a whim, they decided to drive to the beach.

  他们一时兴起，决定开车去海滩。

Impulse and whim both mean a sudden idea to do something. Impulse is stronger, suggesting a hard-to-resist urge, used in the phrase on impulse, without an article. Whim is lighter and more playful, often trivial, used with an article, as in a whim.

这两个词都表示“一时的念头或冲动”，语境相近，但impulse更强调强烈、难以控制的冲动，语气较重；whim则更随性，带有一点任性或不太认真的意味，语气较轻。此外，whim常带冠词构成“on a whim”，impulse则用不带冠词的“on impulse”。