be all Greek to someone
(it's) (all) Greek to me
cliché This might as well be a foreign language, because I don't understand it at all. The phrase comes from Shakespeare's play Julius Caesar. Can you make sense of these instructions? It's all Greek to me!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
be all Greek to someoneBRITISH, AMERICAN or
be Greek to someoneAMERICAN
If you say that something is all Greek to you, you mean that you do not understand it at all. I've no idea what it means — it's all Greek to me. I don't understand legal jargon — it's all Greek to me. Note: The idea behind this expression is that Greek is very difficult to learn and understand, especially because it uses a different alphabet from most other European languages.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012