Greek to me - Wikipedia

That's Greek to me or it's (all) Greek to me is an idiom in English referring to material that the speaker finds difficult or impossible to understand. It is commonly used in reference to a complex or imprecise verbal or written expression, that may use unfamiliar jargon, dialect, or symbols. The metaphor refers to the Greek language, which is unfamiliar to most English speakers, and additionally

[itochan]

これ

[shuzo_kino]

各国の Greek to me 系慣用句の一覧。中国語とギリシャ語が二強か。あと、チンプンカンプンに漢字あてられてるのな。