‘冷汗’ literally means 'cold sweat'—a physical reaction where a person sweats unexpectedly, often due to fear, anxiety, shock, or intense stress. The character 冷 (lěng) means 'cold', and 汗 (hàn) means 'sweat'; together, they describe sweat that feels cool or clammy on the skin, unlike regular sweat caused by heat or exercise. This phrase emphasizes the emotional or physiological trigger rather than temperature alone.

It’s commonly used in spoken and written Chinese to convey sudden nervousness, panic, or dread—for example, before an important exam, during a frightening encounter, or when facing bad news. While it refers to real perspiration, ‘冷汗’ is also frequently used figuratively to express deep unease or alarm, even without actual sweating. It appears in both everyday conversation and literature, often paired with verbs like 冒 (mào, 'to break out') or 出 (chū, 'to appear').