Greek to me, it's

Idioms  

1. Also, it's all Greek to me. It is beyond my comprehension, as in This new computer program is all Greek to me. This expression was coined by Shakespeare, who used it literally in Julius Caesar (1:2), where Casca says of a speech by Seneca, deliberately given in Greek so that some would not understand it, “For mine own part, it was Greek to me.” It soon was transferred to anything unintelligible.

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