petard /pe-tär or -tärdˈ/

1. A case containing an explosive, used for blowing in doors, etc (Shakespeare petarˈ)
2. A moving firework

hoist with one's own petard see under hoist

• efforced
• efforces
• efforcing
• effort
• effortful
• effortfully
• effortless
• effortlessly
• effortlessness
• efforts
• effraide
• effray
• effronteries
• effrontery
• effulge
• effulged
• effulgence
• effulgences
• effulgent
• gruffly
• gruffness
• gruffnesses
• grufted
• gru-gru
• gru-gru worm