‘叹息’ is a formal or literary verb meaning 'to sigh' — to exhale audibly, often expressing sadness, disappointment, weariness, or deep reflection. The first character 叹 (tàn) means 'to exclaim' or 'to lament', while 息 (xī) means 'breath' or 'to breathe'. Together, they literally evoke the image of a heavy, breath-filled exclamation — not just a physical sigh, but one charged with feeling and intention. It appears frequently in written Chinese, classical poetry, novels, and formal speech, less so in casual daily conversation.

This word carries emotional weight and often implies a sense of resignation, sorrow, or quiet contemplation rather than fleeting frustration. It may accompany gestures like bowing the head or pausing thoughtfully. Unlike colloquial alternatives like 唉 (āi) or 啧 (zé), 叹息 conveys depth and gravity — think of someone sighing after hearing tragic news or gazing at an abandoned home. It can also be used reflexively (e.g., 叹息一声) or as a noun ('a sigh'), though its verbal use is primary.