WordNet (r) 3.0 (2006):

costume designer
    n 1: someone who designs or supplies costumes (as for a play or
         masquerade) [syn: costumier, costumer, costume
         designer]

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "costume designer":
   MC, auteur, ballyhoo man, barker, callboy, costumer, costumier,
   couturier, designer, director, dress designer, emcee,
   equestrian director, exhibitor, furniture designer, impresario,
   makeup man, master of ceremonies, playreader, producer, prompter,
   ringmaster, rug designer, scenewright, set designer, showman,
   spieler, stage director, stage manager, styler, stylist,
   theater man, theatrician, ticket collector, usher, usherer,
   usherette