(it's all) Greek to (one)
cliché (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."
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
Greek to (someone)
incomprehensible to someone; 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.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.