Hoisted by one's own petard
Meaning
To be harmed or defeated by one's own scheme or device that was intended to harm others.
Origin
The phrase bursts forth from the dramatic world of Shakespeare's Hamlet, penned around 1600. In the play, Hamlet vows to outmaneuver Rosencrantz and Guildenstern, declaring he will "hoist the enginer with his own petard." But what, exactly, is a "petard"? It was a formidable military device: a small, bell-shaped explosive filled with gunpowder, designed to be attached to gates or walls to blow them open. The engineer, or "enginer," was the person tasked with setting these charges. If the fuse was too short, or the explosive was unstable, the "enginer" could very literally be blown sky-high, "hoisted" into the air by their own destructive device. The phrase quickly shed its literal, gunpowder-laden meaning, evolving into a vivid metaphor for being undone by one's own nefarious plot.
Examples
- The politician's elaborate smear campaign ultimately failed, and he found himself hoisted by his own petard when his own past misdeeds were exposed.
- She tried to sabotage her rival's presentation, but her trick backfired, and she was well and truly hoisted by her own petard.