The Collaborative International Dictionary of English v.0.48:

Playwright \Play"wright`\, n.
   A maker or adapter of plays.
   [1913 Webster]

WordNet (r) 3.0 (2006):

playwright
    n 1: someone who writes plays [syn: dramatist, playwright]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "playwright":
   choreographer, comedian, dramatist, dramatizer, dramaturge, farcer,
   farceur, farceuse, farcist, gagman, joke writer, jokesmith,
   librettist, melodramatist, mimographer, monodramatist, play doctor,
   play fixer, playwriter, scenario writer, scenarioist, scenarist,
   screenwriter, scriptwriter, tragedian