False or deceitful dealing; acting in bad faith; deception by pretending to entertain one set of intentions while acting under the influence of another. See Double dealing, under Dealing. Shak. Syn. -- duplicity. [ 1913 Webster + WordNet 1.5 ]
One who practices double dealing; a deceitful, trickish person; a person who says one thing and does another. L'Estrange. Syn. -- double-crosser, betrayer, traitor. [ 1913 Webster + WordNet 1.5 ]