The Collaborative International Dictionary of English v.0.48:

Swindler \Swin"dler\, n. [G. schwindler, fr. schwindlen to be
   dizzy, to act thoughtlessly, to cheat, fr. schwindel
   dizziness, fr. schwinden to vanish, to disappear, to dwindle.
   See Swim to be dizzy.]
   One who swindles, or defrauds grossly; one who makes a
   practice of defrauding others by imposition or deliberate
   artifice; a cheat.
   [1913 Webster]

   Syn: Sharper; rogue.

   Usage: Swindler, Sharper. These words agree in describing
          persons who take unfair advantages. A swindler is one
          who obtains money or goods under false pretenses. A
          sharper is one who cheats by sharp practice, as in
          playing at cards or staking what he can not pay.
          [1913 Webster]

                Fraud and injustice soon follow, and the dignity
                of the British merchant is sunk in the
                scandalous appellation of a swindler. --V. Knox.
          [1913 Webster]

                Perhaps you 'll think I act the same
                As a sly sharper plays his game.  --Cotton.
          [1913 Webster]

WordNet (r) 3.0 (2006):

swindler
    n 1: a person who swindles you by means of deception or fraud
         [syn: swindler, defrauder, chiseller, chiseler,
         gouger, scammer, grifter]

Moby Thesaurus II by Grady Ward, 1.0:

95 Moby Thesaurus words for "swindler":
   Artful Dodger, Judas, Philadelphia lawyer, Yankee horse trader,
   betrayer, blackleg, body snatcher, booster, bunco steerer,
   charlatan, charmer, cheat, cheater, chicken thief, chiseler,
   come-on, con man, confidence man, convict, cozener, crafty rascal,
   criminal, crook, deceiver, defrauder, den of thieves, desperado,
   desperate criminal, diddler, dodger, double-dealer, embezzler,
   felon, filcher, flimflam man, flimflammer, fox, fraud, fugitive,
   gallows bird, ganef, gangster, gaolbird, ghoul, glib tongue,
   grafter, grave robber, gyp artist, gypper, hoaxer, horse trader,
   jailbird, jewel thief, juggler, knave, land pirate, land shark,
   land-grabber, larcener, larcenist, lawbreaker, lifter, mobster,
   mountebank, outlaw, peculator, petty thief, pilferer, poacher,
   prowler, public enemy, purloiner, quisling, racketeer, reynard,
   robber, scofflaw, scoundrel, scrounger, sharper, shoplifter,
   shyster, slick citizen, sly dog, slyboots, sneak thief, stealer,
   sweet talker, thief, thug, traitor, trickster, two-timer, villain,
   white-collar thief



Bouvier's Law Dictionary, Revised 6th Ed (1856):

SWINDLER, criminal law. A cheat; one guilty of defrauding divers persons. 1
Term Rep. 748; 2 H. Blackst. 531; Stark. on Sland. 135.
     2. Swindling is usually applied to a transaction, where the guilty
party procures the delivery to him, under a pretended contract, of the
personal property of another, with the felonious design of appropriating it
to his own use. 2 Russell on Crimes, 130; Alison, Prine. Cr. Law of
Scotland, 250; Mass. 406.