"Waving sweat like rain" literally means that the sweat thrown off is like rain, describing a large, crowded mass of people or hot weather that causes excessive sweating. It comes from Strategies of the Warring States, Qi Strategies I. The original text reads, "On the roads of Linzi, carriage hubs strike one another, people's shoulders rub together, joined lapels form a curtain, raised sleeves form a canopy, and waving sweat becomes rain," depicting the prosperous scene of Linzi, the capital of the State of Qi, where pedestrians jostled shoulder to shoulder and the sweat they threw off was like rain. This idiom can be used both to describe a scene of dense, overcrowded people and to describe extreme heat or heavy sweating during labor or exercise. It carries an exaggerated rhetorical flavor and is emotionally neutral but vivid, often used to heighten the atmosphere and emphasize the hardship of the environment or the liveliness of the scene. In modern Chinese, it is mostly used to describe labor under high-temperature weather, intense exercise in sports competitions, or crowded public places.
📝 Example
1. Construction workers sweat profusely under the scorching sun, just to complete this bridge as soon as possible. (Describing excessive sweating and hard work)
2. On the Great Wall during the National Day holiday, tourists sweat profusely but remain in high spirits. (Describing large crowds and heavy sweating caused by hot weather)