The Collaborative International Dictionary of English v.0.48:

Gamester \Game"ster\ (g[=a]m"st[~e]r), n. [Game + -ster.]
   1. A merry, frolicsome person. [Obs.] --Shak.
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   2. A person who plays at games; esp., one accustomed to play
      for a stake; a gambler; one skilled in games.
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            When lenity and cruelty play for a kingdom, the
            gentlest gamester is the soonest winner. --Shak.
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   3. A prostitute; a strumpet. [Obs.] --Shak.
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