'用劲' (yòng jìn) is a verb meaning 'to apply strength' or 'to exert force'—literally 'use strength'. The character 用 (yòng) means 'to use', and 劲 (jìn) means 'strength', 'power', or 'effort'. Together, they form a compound verb that emphasizes deliberate physical effort, often in short bursts rather than sustained exertion. It’s commonly used in everyday situations involving pushing, pulling, lifting, twisting, or overcoming resistance.

This expression is informal but widely understood across dialects and age groups. It frequently appears in spoken Chinese and instructional contexts—like fitness coaching, manual tasks, or sports—and often co-occurs with directional complements (e.g., 用劲推, 用劲拉) or degree adverbs (e.g., 使劲, 稍微用劲). While 劲 can also mean 'vital energy' in classical or medical contexts, 用劲 is almost exclusively physical and colloquial.