The Collaborative International Dictionary of English v.0.48:

Dealing \Deal"ing\, n.
   The act of one who deals; distribution of anything, as of
   cards to the players; method of business; traffic;
   intercourse; transaction; as, to have dealings with a person.
   [1913 Webster]

   Double dealing, insincere, treacherous dealing; duplicity.


   Plain dealing, fair, sincere, honorable dealing; honest,
      outspoken expression of opinion.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Double dealing \Dou"ble deal"ing\, double-dealing
\dou"ble-deal"ing\
   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]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "double dealing":
   Machiavellian, Machiavellianism, ambidexterity, ambidextrous,
   artful, artifice, bad faith, chicane, chicanery, crafty, crooked,
   cunning, deceitful, deceitfulness, dirty pool, dirty trick,
   dirty work, dishonest, dishonesty, double, double-faced,
   double-minded, double-tongued, doublehearted, doubleness,
   doubleness of heart, duplicitous, duplicity, faithless,
   faithlessness, false, false-principled, falsehearted,
   falseheartedness, falseness, foul play, fraud, hanky-panky,
   hypocritical, improbity, left-handed, low cunning, perfidious,
   perfidiousness, perfidy, sharp practice, shifty, slippery,
   treacherous, treacherousness, treachery, trickery, tricky,
   two-faced, two-facedness, wile