以子之矛,攻子之盾 [ㄧˇ ㄗˇ ㄓ ㄇㄠˊ , ㄍㄨㄥ ㄗˇ ㄓ ㄉㄨㄣˋ; yi3 zi3 zhi1 mao2 , gong1 zi3 zhi1 dun4]
lit. use sb's spear to attack his shield (idiom, derived from Han Feizi 韓非子); turning a weapon against its owner
fig. to attack an opponent using his own devices
hoist with his own petard
◄ ►