一刀两断

一刀两断:

Literally means:

cut it in half with a knife

Actually means:

break off all relations with

It means making a clean break of something with the knife so that the two halves cannot be rejoined.

It figuratively means making a resolute break with someone or something, usually used to refer to breaking love or friendship.

用刀切东西，一刀切下去，东西变成两部分，互相再也连不起来了。

比喻坚决果断地断绝关>多用来指情感上的决裂，或交往的断绝。