神疲力惫 is a formal, literary Chinese compound adjective meaning 'spiritually and physically exhausted' — conveying total depletion of both mental energy (神, 'spirit/mind') and physical strength (力, 'strength'; 惫, 'extreme fatigue'). The character 疲 reinforces general weariness, while 惫 intensifies it to the point of utter exhaustion. Together, the four characters create a vivid, emphatic description of profound fatigue affecting the whole person.

This term is commonly used in medical contexts, classical literature, and formal writing to describe severe exhaustion resulting from prolonged illness, overwork, or emotional strain. It’s stronger than everyday terms like 累 (lèi, 'tired') and carries a tone of seriousness or gravity — rarely used in casual speech. While grammatically an adjective, it often functions predicatively (e.g., 他神疲力惫) or attributively before nouns in written style (e.g., 神疲力惫的状态).