痛快 (tòng kuài) is an adjective describing a feeling of deep, unreserved satisfaction or exhilaration—often after releasing pent-up emotion, overcoming difficulty, or enjoying something intensely. Literally, 痛 means 'pain' and 快 means 'happy' or 'fast', but together they form an idiom meaning 'refreshingly freeing': the 'pain' suggests intensity or thoroughness, while 'fast' conveys immediacy and ease—so the compound evokes a sudden, cleansing release of tension followed by joy.

This word is commonly used to describe satisfying experiences like a good laugh, a candid conversation, a decisive action, or even physical relief (e.g., after sweating during exercise or drinking cold water on a hot day). It carries positive emotional weight and often implies authenticity, spontaneity, and emotional honesty—never restraint or hesitation. While it can modify verbs (e.g., 痛快地笑), it most frequently functions predicatively (e.g., 这真痛快！) or attributively before nouns like 痛快的感觉 ('a refreshing feeling').