The Collaborative International Dictionary of English v.0.48:

Deceit \De*ceit"\, n. [OF. deceit, des[,c]ait, decept (cf.
   deceite, de[,c]oite), fr. L. deceptus deception, fr.
   decipere. See Deceive.]
   1. An attempt or disposition to deceive or lead into error;
      any declaration, artifice, or practice, which misleads
      another, or causes him to believe what is false; a
      contrivance to entrap; deception; a wily device; fraud.
      [1913 Webster]

            Making the ephah small and the shekel great, and
            falsifying the balances by deceit.    --Amos viii.
                                                  5.
      [1913 Webster]

            Friendly to man, far from deceit or guile. --Milton.
      [1913 Webster]

            Yet still we hug the dear deceit.     --N. Cotton.
      [1913 Webster]

   2. (Law) Any trick, collusion, contrivance, false
      representation, or underhand practice, used to defraud
      another. When injury is thereby effected, an action of
      deceit, as it called, lies for compensation.

   Syn: Deception; fraud; imposition; duplicity; trickery;
        guile; falsifying; double-dealing; stratagem. See
        Deception.
        [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

90 Moby Thesaurus words for "deceit":
   art, artful dodge, artfulness, artifice, blind, cheating, chicane,
   chicanery, con, con game, conspiracy, contrivance, coup, craft,
   craftiness, cunning, cute trick, deceitfulness, deception,
   defrauding, design, device, dishonesty, dissemblance,
   dissimulation, dodge, double-cross, double-dealing, duplicity,
   expedient, fakement, falseheartedness, falseness, feint, fetch,
   flam, flimflam, fraud, fraudulence, furtiveness, gambit, game,
   gimmick, grift, guile, gyp, hanky-panky, hoax, humbug, hypocrisy,
   indirection, insidiousness, intrigue, jugglery, knavery,
   little game, maneuver, misrepresentation, monkey business, move,
   overreaching, plot, ploy, racket, red herring, ruse, scam, scheme,
   sell, sham, shift, shiftiness, sleight, slyness, sneak attack,
   sneakiness, stratagem, strategy, subterfuge, surreptitiousness,
   swindle, tactic, trapping, treacherousness, treachery, trick,
   trickery, underhandedness, wile, wily device