A con artist; someone who pulls confidence games; a swindler, scammer, huckster, hustler, and/or charlatan.
A manipulator or otherwise generally corrupt person who "games" a system, group of people, or other entity for selfish gains; especially of a political "sell-out" perceived as lacking integrity.
A skillful, manipulative person, con artist, or clever scoundrel.
A person who accomplishes tasks with efficiency and grace, especially one with verbal skills who is persuasive in interpersonal relationships, negotiation, etc.