替身 (tì shēn) literally means 'substitute body' — 替 (tì) means 'to replace' or 'to stand in for', and 身 (shēn) means 'body' or 'person'. Together, the term refers to a person who takes another’s place, most commonly in film or television as a stunt double who performs dangerous actions for an actor. It can also refer more broadly to any stand-in — such as a backup performer, a proxy in a ceremony, or even a scapegoat in informal or literary contexts.

In everyday usage, 替身 is neutral but leans formal or professional when referring to film work; in metaphorical or humorous use (e.g., 'I’m just his 替身 at meetings'), it may carry mild irony or self-deprecation. Unlike generic synonyms like 代替者, 替身 strongly implies physical substitution — especially where appearance, movement, or risk is involved — and often suggests temporary, role-specific replacement rather than permanent succession.