beats me
(idiomatic, as response or with indirect question) I don't know; I have no idea.
Do you have any idea what "tergiversate" means? Beats me!
Beats me how he finds out when we're goofing off.
I have a superstition about saying too much about what I want to happen, just in case it all disappears, or someone else comes along and beats me to it. Gil Gerard
What beats me - it always does - is how a man can be so clever and yet be such a perfect fool. Agatha Christie
I'm a competitor and a very proud man. If a guy beats me once, he'll have to do it again to make me believe him. Sugar Ray Leonard
I'll tell you where he beats me though and where he beats the world. He doesn't give a damn about what the enemy does out of his sight, but it scares me like hell. William Tecumseh Sherman