A ploy is a clever plan that helps you get what you want. A manipulative little girl might shed tears simply as a ploy to get her mother to buy her ice cream.
A politician might add amendments to a bill as a ploy to delay voting, or a hooligan might yell, "Fire!" in a movie theater as a ploy to sneak his friends in. A sneaky move in a game is a ploy, and sensational news about a celebrity can be just a ploy to get him more media attention. The first recorded use of ploy was in 1722, meaning "anything with which one amuses oneself" in Scottish and Northern English dialects.