https://grammarist.com/idiom/its-greek-to-me-and-its-all-greek-to-me/ https://grammarist.com/idiom/its-greek-to-me-and-its-all-gre... Popularized by Shakespear

https://grammarist.com/idiom/its-greek-to-me-and-its-all-greek-to-me/ https://grammarist.com/idiom/its-greek-to-me-and-its-all-gre... Popularized by Shakespeare, but predates him as a latin phrase used by scribes: Graecum est; non legitur, which means “It is Greek and therefore is impossible to read.”