The Collaborative International Dictionary of English v.0.48:

Player \Play"er\, n.
   1. One who plays, or amuses himself; one without serious
      aims; an idler; a trifler. --Shak.
      [1913 Webster]

   2. One who plays any game.
      [1913 Webster]

   3. A dramatic actor. --Shak.
      [1913 Webster]

   4. One who plays on an instrument of music. "A cunning player
      on a harp." --1 Sam. xvi. 16.
      [1913 Webster]

   5. A gamester; a gambler.
      [1913 Webster]

WordNet (r) 3.0 (2006):

player
    n 1: a person who participates in or is skilled at some game
         [syn: player, participant]
    2: someone who plays a musical instrument (as a profession)
       [syn: musician, instrumentalist, player]
    3: a theatrical performer [syn: actor, histrion, player,
       thespian, role player]
    4: a person who pursues a number of different social and sexual
       partners simultaneously
    5: an important participant (as in a business deal); "he was a
       major player in setting up the corporation"