The Collaborative International Dictionary of English v.0.48:

Mummer \Mumm"er\, n. [Cf. OF. mommeur. See Mumm, and cf.
   Momier.]
   One who mumms, or makes diversion in disguise; a masker; a
   buffon.
   [1913 Webster]

         Jugglers and dancers, antics, mummers.   --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

mummer
    n 1: an actor who communicates entirely by gesture and facial
         expression [syn: mime, mimer, mummer, pantomimer,
         pantomimist]

Moby Thesaurus II by Grady Ward, 1.0:

84 Moby Thesaurus words for "mummer":
   Roscius, actor, actress, antagonist, artist, artiste, bad guy,
   barnstormer, belly dancer, burlesque queen, character,
   character actor, character man, character woman, child actor,
   chorine, chorus boy, chorus girl, conjurer, coryphee, dancer,
   dancing girl, diseur, diseuse, dramatizer, ecdysiast, entertainer,
   exotic dancer, feeder, female impersonator, foil, geisha,
   geisha girl, guisard, guiser, heavy, histrio, histrion, hoofer,
   impersonator, incognita, incognito, ingenue, juvenile, magician,
   masker, masquerader, matinee idol, mime, mimer, mimic, monologist,
   mountebank, musician, nautch girl, pantomime, pantomimist, peeler,
   performer, playactor, player, prestidigitator, protean actor,
   public entertainer, reciter, show girl, singer, soubrette,
   stage performer, stage player, stooge, straight man, stripper,
   stripteaser, stripteuse, stroller, strolling player, theatrical,
   thespian, trouper, utility man, vaudevillian, vaudevillist,
   villain