The Collaborative International Dictionary of English v.0.48:

Treacher \Treach"er\, n. [OE. trichour, trichur, OF. tricheor
   deceiver, traitor, F. tricheur a cheat at play, a trickster.
   See Treachery.]
   A traitor; a cheat. [Obs.]
   [1913 Webster]

         Treacher and coward both.                --Beau. & Fl.
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