大胆 (dà dǎn) is an adjective meaning 'bold, daring' — it describes a person, idea, or action that takes risks without fear. It differs from 勇敢 (yǒng gǎn, 'brave'), which emphasizes courage in the face of danger or hardship, and from the verb 敢 (gǎn, 'to dare'), which is used before another verb (e.g., 敢说 'dare to speak'). 大胆 is the everyday word for being audacious in a neutral or positive sense.