Dramatist
A dramatist is an author of dramatic compositions for the theater. The compositions meant are typically plays, although the term may also describe authors and composers in related fields such as opera and musical theater. An actor who performs the drama may also sometimes be called a dramatist.The reference to drama means that dramatist is sometimes reserved for those who have written "serious" plays, as opposed to comedies or farces. A more general term for an author of plays, of whatever type, is playwright.
See also: List of playwrights