2tái chēung 替槍 — a stand-in; a person who takes on the name or the role of another in doing a task for the benefit of someone who is unable to do it well on their own (e.g. one student writing a paper for another, a "ghost writer" writing a newspaper column for a celebrity).
3tái séi 替死 — to stand in for someone, to take someone's place, to substitute for someone; to sacrifice oneself for someone.
4tái séi gwáai 替死鬼 — a scapegoat, a "fall-guy", a substitute victim.