composer UK /kəmˈpəʊzə/US /kəmˈpoʊzəɹ/ noun3 •One who composes; an author. •Especially, one who composes music. •One who, or that which, quiets or calms.The exertion necessary to soothe and subdue Lucy's passionate sorrow was the best composer to Francesca's own agitation. — 1834 formscomposers