sudden

Compared meaning: happening suddenly and unexpectedly (adjective).

比较义项：突然发生、出乎意料的（形容词）。

• sudden 本词

  A general, neutral word for something happening quickly and without warning; it can describe almost any event, decision, or feeling, with no hint about size or tone.

  语气中性、用途最广的词，泛指快速且毫无预兆发生的事情，可用于几乎任何事件、决定或感受，不暗示变化的幅度或语气。

  Their sudden decision to move abroad surprised the entire family.

  他们突然决定移居国外，让全家人都感到惊讶。

• sharp

  Stresses a sudden change that is also large or marked in degree, typically used with measurable things like prices, temperature, turns, or pain; rarely used for decisions or events themselves.

  强调变化不仅突然，而且幅度明显，常用于价格、温度、转弯、疼痛等可衡量的事物，很少直接修饰决定或事件本身。

  There was a sharp rise in oil prices after the news broke.

  消息传出后，油价出现了急剧上涨。

• abrupt

  Sudden and unexpected, but often carries a negative tone of being curt, rude, or jarring, especially describing the manner of speech, an ending, or a physical turn.

  同样表示突然、出乎意料，但常带有生硬、无礼或令人不适的负面语气，尤其用来形容说话方式、事情的结束或急转的动作。

  His reply was so abrupt that it felt almost rude.

  他的回答如此生硬突然，几乎显得有些无礼。

Sudden, sharp, and abrupt all mean happening suddenly and unexpectedly, but with different tones. Sudden is the most neutral, general word. Sharp stresses a big change in degree. Abrupt often sounds rude or unpleasant. This does not cover sharp meaning to cut, like a knife.

这三个词都表示「突然、出乎意料」，但语气和用法不同：sudden 最中性通用，sharp 强调变化幅度大，abrupt 常带生硬或无礼的意味。这里不比较 sharp 表示「锋利的」的意思（如 sharp knife）。