Understudy

Verb

 * 1) to study or know a role to such an extent as to be able to replace the normal performer when required
 * 2) to act as an understudy (to someone)

Noun

 * 1) a performer who understudies; a standby

Thesaurus
act for, advocate, agent, alter ego, alternate, alternative, amicus curiae, analogy, answer for, appear for, attorney, back up, backup, backup man, bit player, champion, change, change places with, changeling, commission, comparison, copy, counterfeit, crowd out, cut out, deputize, deputy, displace, double, double for, dummy, equal, equivalent, ersatz, exchange, executive officer, exponent, extra, fake, figurant, figurante, figurehead, fill in for, fill-in, front for, ghost, ghostwrite, ghostwriter, imitation, lieutenant, locum, locum tenens, makeshift, metaphor, metonymy, mute, next best thing, paranymph, personnel, phony, pinch hitter, pinch-hit, pinch-hit for, pleader, procurator, proxy, relief, relieve, replace, replacement, represent, representative, reserve, reserves, ringer, second, second in command, second string, secondary, sign, spares, speak for, spear-carrier, spell, spell off, stand in for, stand-in, standby, sub, subrogate, substituent, substitute, substitute for, substitution, succedaneum, succeed, supe, super, supernumerary, supersede, superseder, supplant, supplanter, support, supporting actor, supporting cast, surrogate, swap places with, symbol, synecdoche, third string, token, understudy for, utility man, utility player, vicar, vicar general, vice, vice-president, vice-regent, vicegerent, walk-on, walking gentleman

Noun

 * Finnish:


 * Spanish: