be hoist with (one's) own petard(redirected from be hoist with their own petard)
be hoist with (one's) own petard
To be injured, ruined, or defeated by one's own action, device, or plot that was intended to harm another; to have fallen victim to one's own trap or schemes. ("Hoist" in this instance is the past participle of the archaic form of the verb, "hoise.") I tried to get my boss fired by planting drugs on him, but I was hoist with my own petard when the police caught me with them beforehand.
be hoist with one's own petard
To be undone by one's own schemes.