Someone who deceives you about his true nature or intent in order to take advantage of you.

Roget 792: thief, robber, homo triumliterarum [Lat.], pilferer, rifler, filcher^†, plagiarist.    spoiler, depredator, pillager, marauder; harpy, shark [Slang], land shark, falcon, mosstrooper^†, bushranger^†, Bedouin^†, brigand, freebooter, bandit, thug, dacoit^†; pirate, corsair, viking, Paul Jones^†, buccaneer, buccanier^†; piqueerer^†, pickeerer^†; rover, ranger, privateer, filibuster; rapparee^†, wrecker, picaroon^†; smuggler, poacher; abductor, badger [Slang], bunko man, cattle thief, chor^†, contrabandist^†, crook, hawk, holdup man, hold-up [U.S.], jackleg [U.S.], kidnaper, rustler, cattle rustler, sandbagger, sea king, skin [Slang], sneak thief, spieler^†, strong-arm man [U.S.].    highwayman, Dick Turpin, Claude Duval, Macheath, footpad, sturdy beggar.    cut purse, pick purse; pickpocket, light-fingered gentry; sharper; card sharper, skittle sharper; thimblerigger; rook [Slang], Greek, blackleg, leg, welsher [Slang]; defaulter; Autolycus^†, Jeremy Diddler^†, Robert Macaire, artful dodger, trickster; swell mob [Slang], chevalier d'industrie [Fr.]; shoplifter.    swindler, peculator; forger, coiner; fence, receiver of stolen goods, duffer; smasher.    burglar, housebreaker; cracksman^†, magsman [Slang]; Bill Sikes, Jack Sheppard, Jonathan Wild.    gang [group of thieves], gang of thieves, theft ring; organized crime, mafia, the Sicilian Mafia, the mob, la cosa nostra [It].    [famous thieves], Dillinger, Al Capone; Robin Hood.    ... show more