petard

/pəˈtɑrd/
noun
  1. Used in the phrase 'hoist with one's own petard' meaning to be harmed by one's own plan or device intended to harm others.
    • She tried to spread rumors about her rival, but was hoist with her own petard when the truth came out.
    • The hacker was hoist with his own petard when his virus infected his own computer.
    • The company's dishonest scheme backfired, and they were hoist with their own petard.
  2. A small bomb or explosive device, historically used to break down doors or walls.
    • The museum displayed an old iron petard from the 16th century.
    • The soldiers used a petard to blast open the castle gate.
    • In medieval warfare, a petard was often carried by a sapper.
Synonyms
What does "petard" mean? | whatsthatwordmean | whatsthatwordmean