fǎn​shuǐ​bù​shōu

what is done cannot be undone

Senses

反水不收 fǎn​shuǐ​bù​shōu what is done cannot be undone

literally meaning spilled water cannot be gathered up again, this idiom describes a situation that has reached a point of no return where regret is useless

References

same_as 反水不收/反水不收 覆水难收/覆水難收