垂涎 literally means 'to let saliva drip down' — 垂 (chuí) means 'to hang down' or 'to droop', and 涎 (xián) means 'saliva'. Together, they form a vivid, slightly literary verb describing an intense, almost physical desire — like someone salivating at the sight of delicious food. While it can refer to literal drooling (especially in descriptive or humorous contexts), it’s far more common in figurative usage to express strong longing or covetousness for something desirable: wealth, status, opportunities, or attractive people.

This word carries a subtle tone of greed or unseemly eagerness, so it’s often used critically or with irony — for example, to describe someone eyeing another’s promotion or luxury car. It appears frequently in written Chinese (essays, news, literature) and formal speech, but is less common in casual daily conversation, where simpler terms like 羡慕 (xiànmù, 'to admire') or 想要 (xiǎng yào, 'to want') are preferred.