匆匆 (cōng cōng) is a reduplicated adverb meaning 'hastily', 'in a rush', or 'in haste'. Though each character 匆 on its own can mean 'hurried' or 'sudden', together they intensify the sense of urgency and brevity — like someone moving quickly without pausing or lingering. It often describes actions done with little time, attention, or preparation, such as leaving, eating, or glancing.

This word frequently appears in literary or descriptive contexts, especially in written Chinese and formal speech, but it’s also common in everyday spoken language when expressing rushed behavior. It typically modifies verbs (e.g., 匆匆离开, 匆匆吃完), and may appear before or after the verb depending on emphasis. Unlike many monosyllabic adverbs, 匆匆 is almost always used in this doubled form — the single character 匆 rarely stands alone in modern usage.