骤降 literally combines 骤 (zhòu), meaning 'sudden' or 'abrupt', and 降 (jiàng), meaning 'to descend' or 'to fall'. Together, they form a verb meaning 'to plummet suddenly' — describing a rapid, sharp drop in something measurable, most commonly temperature, stock prices, air pressure, or water levels. It carries a sense of urgency and intensity, often implying an unexpected or dramatic change.

This word is frequently used in weather reports, financial news, and scientific contexts. It’s more formal and emphatic than simpler verbs like 下降 (xiàjiàng) or 降低 (dījiàng), and almost always modifies a noun indicating what is falling — e.g., 气温骤降 (temperature plummets), 股价骤降 (stock price plummets). It does not function as a standalone action verb; it requires a subject and a clear metric of decline.