n. something incomprehensible to someone; something as mysterious as Greek writing.
I don't understand this. It's all Greek to me.She said it was Greek to her, and that it made no sense at all.
(it's all) Greek to (one)
(It is) completely unintelligible, as if it is written in a language that one does not speak. The phrase comes from Shakespeare's play Julius Caesar. Mom said these instructions are Greek to her and that we should show them to Dad.A: "Can you understand this error message?" B: "Sorry, Greek to me. You'd better ask one of the programmers."
Greek to someone
n. something incomprehensible to someone; something as mysterious as Greek writing. I don’t understand this. It’s all Greek to me.