confidence game

from The American Heritage® Dictionary of the English Language, 4th Edition

• n. A swindle in which the victim is defrauded after his or her confidence has been won.

from Wiktionary, Creative Commons Attribution/Share-Alike License

• n. A swindle in which the mark, or victim, is defrauded after his or her trust has been won.

from the GNU version of the Collaborative International Dictionary of English

• n. any swindling operation in which advantage is taken of the confidence reposed by the victim in the swindler; several swindlers often work together to create the illusion of truth; -- also called con game.
• n. See under Confidence.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• n. a swindle in which you cheat at gambling or persuade a person to buy worthless property