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]

The Collaborative International Dictionary of English v.0.48:

double-dealing \double-dealing\ adj.
   1. given to deception especially by pretending one set of
      feelings and acting under the influence of another; as,
      they accused each other of double-dealing behavior.

   Syn: ambidextrous, deceitful, duplicitous, two-faced.
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

double-dealing
    adj 1: marked by deliberate deceptiveness especially by
           pretending one set of feelings and acting under the
           influence of another; "she was a deceitful scheming
           little thing"- Israel Zangwill; "a double-dealing double
           agent"; "a double-faced infernal traitor and schemer"-
           W.M.Thackeray [syn: ambidextrous, deceitful, double-
           dealing, duplicitous, Janus-faced, two-faced,
           double-faced, double-tongued]
    n 1: acting in bad faith; deception by pretending to entertain
         one set of intentions while acting under the influence of
         another [syn: duplicity, double-dealing]