疲惫 is an adjective meaning 'exhausted' or 'worn out' — describing a state of extreme physical or mental tiredness, often after prolonged effort, stress, or lack of rest. The character 疲 (pí) means 'tired' or 'fatigued', and 惫 (bèi) intensifies the sense, carrying connotations of depletion and exhaustion. Together, they form a compound that emphasizes deep, overwhelming weariness — stronger than just 累 (lèi) and more formal or literary than everyday terms like 困 (kùn).

This word is commonly used in written Chinese and formal speech, especially when describing the aftermath of demanding work, illness, travel, or emotional strain. It often appears in contexts involving health recovery, workplace well-being, or personal reflection. While it can describe people directly (e.g., 他看起来很疲惫), it’s also frequently used attributively before nouns (e.g., 疲惫的身体, 'exhausted body') or predicatively with 是...的 or 很 structures.