fight like Kilkenny cats 死拼；打得两败俱伤，斗个你死我活

【例句】
The two men fought for the girl, over a period of months, but it was a Kilkenny cat fight.
那两个男人为了争那个姑娘而连续斗了几个月，但那是一场两败俱伤的争斗。

Those two children will fight like Kilkenny cats if I leave them alone in the house.
如果我让那两个孩子自己呆在家里，他们一定会打得头破血流。