advocate agent alter ego alternate alternative amicus curiae analogy assistant attorney backup backup man bit player champion change changeling comparison copy counterfeit deputy double dummy equal equivalent ersatz exchange executive officer exponent extra fake figurant figurante figurehead fill-in ghost ghostwriter imitation lieutenant locum locum tenens makeshift metaphor metonymy mute next best thing paranymph personnel phony pinch hitter pleader procurator proxy relief replacement representative reserves ringer second second in command second string secondary sign spares spear-carrier standby sub substituent substitute substitution succedaneum supe super supernumerary superseder supplanter support supporting actor supporting cast surrogate symbol synecdoche third string token understudy utility man utility player vicar vicar general vice vice-president vice-regent vicegerent walk-on walking gentleman