[yǐ zǐ zhī máo, gōng zǐ zhī dùn, ㄧˇ ㄗˇ ㄓ ㄇㄠˊ, ㄍㄨㄥ ㄗˇ ㄓ ㄉㄨㄣˋ, 以子之矛，攻子之盾] lit. use sb's spear to attack his shield (成语 saw, 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 [Add to Longdo]