petard
/peˈtɑːd/noun
1- historical a small bomb made of a metal or wooden box filled with powder, used to blast down a door or to make a hole in a wall〈史〉（由金属或木头盒子装上炸药制成的用于炸门或在墙上炸洞的）攻城炸药箱。
1.1
- a kind of firework that explodes with a sharp report爆竹, 炮仗。
短语
hoist with（或 by）one's own petard
- have one's plans to cause trouble for others backfire on one搬起石头砸自己的脚; 害人反害己。
- [ORIGIN: from Shakespeare's Hamlet （iii. iv. 207）; hoist is in the sense 'lifted and removed', past participle of dialect hoise （see HOIST）.]
词源
mid 16th cent.: from French pétard, from péter 'break wind'.