To no avil...WHAT?!

EDIT: Oh my God, I feel so stupid now. I am not a native English speaker and it confuses and angers me to no end when someone misspells words continuously, especially when I learn to spell them the wrong way from them. I've just got a message from someone, telling me that it should be 'to no avail'.

I've seen people use that phrase at least a dozen times and it always confuses me. "I've been trying this for ages and it's to no avil." Is it misspelled or something? Because I can't find the definition in any dictionary. I had tried searching EVERYWHERE before going here. I know that it means something like 'but it was no success', BUT is it a real phrase or was it made up just like that?

I'd appreciate your help very much.

Thank you,

Marina