比喻以对方的观点、理论来反驳对方。语本《韩非子・难一》：“楚人有鬻楯与矛者，誉之曰：『吾楯之坚，物莫能陷也。』又誉其矛曰：『吾矛之利，于物无不陷也。』或曰：『以子之矛，陷子之楯何如？其人弗能应也。』”
英语 refute somebody with his own way（turn somebody's battery against himself）
