sad

Compared meaning: feeling sad or gloomy (adjective).

比较义项：悲伤、忧郁的情绪（形容词）。

• sad 本词

  The everyday, neutral word for feeling unhappy about something specific; simple in register and used in all contexts, spoken or written.

  最普通、最中性的表示因某事而难过的词；语域简单，口语书面均可使用。

  He was sad about failing the exam, and he cried that night.

  他因考试不及格而难过，那天晚上哭了。

• melancholy

  Describes a deeper, more thoughtful and lingering sadness, often without a clear cause; more literary and formal than sad.

  形容一种更深沉、若有所思且持续较久的忧郁情绪，常常没有明确原因；比 sad 更书面、更正式。

  A melancholy mood settled over the old house as the autumn leaves fell.

  随着秋叶飘落，一种忧郁的气氛笼罩了这栋老房子。

• wistful

  Sadness mixed with quiet longing for something lost or unattainable, often shown through a look, smile, or sigh.

  带有淡淡渴望或怀念意味的伤感，常常通过眼神、微笑或叹息流露出来，多与失去或难以得到的事物有关。

  She smiled wistfully at photos of her childhood home, wishing she could go back.

  她望着儿时家的照片，惆怅地笑了笑，希望自己能回去。

Sad, melancholy, and wistful describe unhappy feelings, but differ in tone. Sad is the direct word for any unhappy situation. Melancholy is a deeper, thoughtful sadness with no clear cause, more formal. Wistful is sadness mixed with longing for something lost, shown by a sigh.

这三个词都形容悲伤的情绪，但语气和用法有别：sad 最常用、最直接，可用于任何令人难过的事情；melancholy 强调一种深沉、若有所思的忧郁情绪，语域更正式、更书面；wistful 则是夹杂着渴望或怀念的淡淡感伤，常通过表情或眼神流露。