Source : CEDICT

lit. use sb's spear to attack his shield (idiom, derived from Han Feizi 韓非子|韩非子); turning a weapon against its owner/fig. to attack an opponent using his own devices/hoist with his own petard

Source : CEDICT

lit. use sb's spear to attack his shield (idiom, derived from Han Feizi 韓非子|韩非子); turning a weapon against its owner/fig. to attack an opponent using his own devices/hoist with his own petard