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!
See also: Greek
Farlex Dictionary of Idioms.

be all Greek to someone

BRITISH, AMERICAN or

be Greek to someone

AMERICAN
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.
See also: all, Greek, someone
Collins COBUILD Idioms Dictionary, 3rd ed.
See also:
  • (it's) (all) Greek to me
  • Greek to me
  • Greek to me, it's
  • it's all Greek to me
  • Greek to someone
  • Greek
  • Greek to
  • (it's all) Greek to (one)
  • (good) black don't crack
  • thicken