hoist with one's own petard or hoist by one's own petard
: victimized or hurt by one's own scheme
Did You Know?
Did you know? The connection between "hoise" and "hoist" is a bit confusing. The two words are essentially synonymous variants, but "hoist" is far more common. You'll rarely encounter "hoise" in any of its regular forms: "hoise," "hoised," or "hoising." But a variant of its past participle shows up fairly frequently as part of a set expression. And now, here's the confusing part-that variant past participle is "hoist"! The expression is "hoist with (or by) one's own petard," which means "victimized or hurt by one's own scheme." This oft-heard phrase owes its popularity to Shakespeare's Hamlet: "For 'tis the sport to have the engineer hoist with his own petar[d]." (A petard is a medieval explosive. The quote implies that the engineer-the person who sets the explosive device-is blown into the air by the explosion of his own device.)