From compose + -er.

• (America) enPR: kəm-pōzʹər, IPA: /kəmˈpoʊzəɹ/
• (RP) enPR: kəm-pōzʹər, IPA: /kəmˈpəʊzə/

composer (plural composers)

1. One who composes; an author.
   1. Especially, one who composes music.
2. One who, or that which, quiets or calms.
   • 1834, L[etitia] E[lizabeth] L[andon], chapter VI, in Francesca Carrara. […], volume III, London: Richard Bentley, […], (successor to Henry Colburn), →OCLC ↗, page 43 ↗:

     The exertion necessary to soothe and subdue Lucy's passionate sorrow was the best composer to Francesca's own agitation.

   • 1713, Joseph Trapp, Musicus Apparatus Academicus set to music by William Croft, pages 38–41, [https://www.digitale-sammlungen.de/de/view/bsb11134816?page=,1 →MDZ]:

     Where, mighty Anna, will thy Glories end.
     Thou Great Composer of distracted states.

• German: Autor
• Portuguese: compositor, criador
• Russian: состави́тель

• French: compositeur, compositrice
• German: Komponist, Komponistin, Tondichter, Tondichterin, Tonkünstler, Tonkünstlerin, Tonschöpfer, Tonschöpferin, Kompositeur, Kompositeurin, Tonsetzer, Tonsetzerin, Musikkomponist, Musikkomponistin
• Italian: compositore, compositrice
• Portuguese: compositor, compositora
• Russian: компози́тор
• Spanish: compositor, compositora

• Portuguese: acalmador
• Russian: успокоитель