To No Avail
But aren't you using the term in a sentence?
You can use more or less at will: but it doesn't work or it's free
Example: I tried to explain the answer in such a way that it would be understood, but without success, we do not speak the same language.
Definition of availability
I tried to stop him from asking questions in the answers, but to no avail.
He tried to get the car stuck in the mud, but to no avail. This is very difficult.
It means trying in vain.
I tried my best to stop labor, but now I have stopped.
But what is the part of sch here?