costumier

This term specifically denotes a professional role within the entertainment industry or specialized retail. While a tailor or seamstress focuses on general garment construction, a costumier specializes in the artistic and historical accuracy required for stage and screen, often blending craftsmanship with theatrical design.

In professional contexts, the term encompasses a wide range of activities, from the initial sourcing of vintage fabrics to the final fitting of an actor. It is more precise than "costume designer," as the costumier is often the individual responsible for the physical execution and maintenance of the wardrobe.