The Collaborative International Dictionary of English v.0.48:

Performer \Per*form"er\, n.
   One who performs, accomplishes, or fulfills; as, a good
   promiser, but a bad performer; especially, one who shows
   skill and training in any art; as, a performer of the drama;
   a performer on the harp.
   [1913 Webster]

WordNet (r) 3.0 (2006):

performer
    n 1: an entertainer who performs a dramatic or musical work for
         an audience [syn: performer, performing artist]

Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "performer":
   actor, actress, affecter, agent, architect, artist, artiste,
   author, belly dancer, burlesque queen, chorine, chorus boy,
   chorus girl, concert artist, conjurer, coryphee, creator, dancer,
   dancing girl, deceiver, doer, ecdysiast, entertainer, executant,
   executor, executrix, exotic dancer, fabricator, fake,
   female impersonator, fraud, geisha, geisha girl, guisard, guiser,
   hollow man, hoofer, impersonator, interpreter, maestro, magician,
   maker, man of straw, mannerist, medium, mime, mimic, minstrel,
   minstrelsy, mountebank, mover, mummer, music maker, musician,
   nautch girl, operant, operative, operator, paper tiger, peeler,
   perpetrator, phony, playactor, player, practitioner,
   prestidigitator, pretender, prime mover, producer,
   public entertainer, show girl, singer, soloist, straw man,
   stripper, stripteaser, stripteuse, subject, thespian, trouper,
   tunester, vaudevillian, vaudevillist, virtuosa, virtuoso, worker