“以牙还牙”，意思是用牙咬来对付牙咬，比喻用对方使用的手段来回击对方，以同样的方式报复，常与“以眼还眼”连用。可以翻译为“engage in a tit for tat”，英文习语“tit for tat”表示“a situation in which you do something to harm someone who has done something harmful to you”。

例句：

这种以牙还牙的报复还要持续多长时间？

How much longer is this tit for tat going to last?

一个贩毒团伙的头目被对立的帮派枪杀了，于是这个团伙展开报复行动。这导致双方以牙还牙的交恶，从谋杀、绑架到纵火，整个城市因此陷入瘫痪状态。

A gang of drug dealers wanted to punish a rival gang for shooting their leader. That led to a tit for tat series of murders, kidnappings and arson that has paralyzed the city.