下不为例

下不为例

Literally means:

not to be taken as precedent not to be repeated

Actually means:

There are things that should not be done. If one does it this time, we will let him go without punishment, but it should not be taken as a precedent.

This phrase is used to remind or warn people that one will not be forgiven the second time for the same mistake.

When used in the negative form, it means that such a mistake is so serious that even the first offence is not forgivable.

有些事情按理是不应该做的，这次既然做了就按是不算了，但不能以此为例，下一次又这么做。

多用来提醒或警告别人:原谅只有这一次，不可能再有第二次。

在否定句中表示连这一次也不可以做。