付东流

付东流

Literally means:

go down the drain; cast to the winds

Actually means:

be in vain

东流 refers to a river that runs eastward into the sea.

The phrase literally means casting something into such a river, and it metaphorically means that one's hope is gone or that one's efforts are futile.

东流，向东流入大海的江河。

付东流，把东西扔进向东流的水中。比喻希望落空或以前的努力白费了。