Greek to me

The strangeness of the greek alphabet, and the confusion caused by having to learn the classics has no doubt donated this interesting idiom to the English language.

Synonyms:

ambiguous, double Dutch, equivocal, fathomless, Greek, illegible, impenetrable, inarticulate, incognizable, incoherent, incomprehensible, indecipherable, indistinct, inexplicit, jumbled, meaningless, muddled, obscure, opaque, tenebrous, uncertain, unclear, unexplicit, unfathomable, ungraspable, unreadable, vague