From Longman Dictionary of Contemporary English(it) beats me(it) beats meUNDERSTANDused to say that you do not know something, or cannot understand or explain it Beats me why he wants such a big car. ‘What’s he saying?’ ‘Beats me.’ → beat
Examples from the Corpus
(it) beats me• How do you measure such a thing? Beats me.• There's only one thing beats me.• Though why he wants to call himself a doctor beats me.• If he beats me at this game, well, he beats me.• It beats me how these kids can afford to spend so much money on clothes and CDs.• Though why the Good Lord didn't strike Durham itself beats me, instead of causing us all this trouble.• Well, I don't fight, he beats me up - it's my fault, I provoke him.• Pretty secluded. Beats me what he does. 