Āi qī is a formal, literary noun meaning 'grief' or 'sorrow'—a deep, solemn feeling of sadness, often tied to loss, mourning, or profound disappointment. The character 哀 (āi) itself means 'sorrow' or 'mourning', carrying connotations of lamentation and heartfelt pain; 戚 (qī) originally referred to relatives but evolved to mean 'distress' or 'anxiety', especially in classical usage. Together, they form a compound that emphasizes the intensity and gravity of emotional suffering—not everyday sadness, but the kind associated with funerals, national tragedies, or irreversible personal loss.

This term appears frequently in written Chinese—especially in literature, obituaries, historical accounts, and formal speeches—but is rarely used in casual speech. It carries a dignified, almost poetic weight, and is often paired with words like 深重 (shēnzhòng, 'profound'), 表达 (biǎodá, 'to express'), or 沉浸在 (chénjìn zài, 'to be immersed in'). Its tone is somber and respectful, never flippant or exaggerated.