[syn: ambidextrous, deceitful, double-dealing, duplicitous, Janus-faced, two-faced, double-faced, double-tongued]
The Collaborative International Dictionary of English v.0.48:
Deceitful \De*ceit"ful\, a.
   Full of, or characterized by, deceit; serving to mislead or
   insnare; trickish; fraudulent; cheating; insincere.
   [1913 Webster]
         Harboring foul deceitful thoughts.       --Shak.
   [1913 Webster]
WordNet (r) 3.0 (2006):
deceitful
    adj 1: intended to deceive; "deceitful advertising"; "fallacious
           testimony"; "smooth, shining, and deceitful as thin ice"
           - S.T.Coleridge; "a fraudulent scheme to escape paying
           taxes" [syn: deceitful, fallacious, fraudulent]
    2: 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]
Moby Thesaurus II by Grady Ward, 1.0:
99 Moby Thesaurus words for "deceitful":
   Machiavellian, Machiavellic, acute, ambidextrous, arch, artful,
   astute, cagey, calculating, canny, chiseling, clandestine, clever,
   collusive, counterfeit, covinous, crafty, crooked, cunning, cute,
   deceptive, deep, deep-laid, delusive, delusory, designing,
   diplomatic, dishonest, disingenuous, double, double-dealing,
   double-faced, double-minded, double-tongued, doublehearted,
   duplicitous, faithless, false, false-principled, falsehearted,
   feline, finagling, forsworn, foxy, fraudulent, furtive, guileful,
   hypocritical, indirect, ingenious, insidious, insincere, inventive,
   knavish, knowing, lying, mendacious, misleading, pawky, perfidious,
   perjured, politic, ready, resourceful, roguish, scheming,
   serpentine, sharp, shifty, shrewd, slick, slippery, sly, smooth,
   snaky, sneaky, sophistical, stealthy, strategic, subtile, subtle,
   supple, surreptitious, tactical, treacherous, trickish, tricksy,
   tricky, two-faced, uncandid, underhand, underhanded, unfrank,
   unsincere, untrustworthy, untruthful, vulpine, wary, wily