executant

noun2

1. •
   A person who executes a dance or piece of music; a performer.

   • […] no composer or dramatic poet has ever pretended to be able to perform all the parts he writes for the singers, actors and players who are his executants. — 1987
2. •
   A person who puts something into action, such as a plan or design.

   • Also of importance are the other theatricians - the costume designer and/or executant, the lighting designer and/or executant, the technical director, […] — 1991