| Greek(unfathomable, impenetrable, opaque, unintelligible, puzzling) |
| beyond comprehension(expression, unfathomable, impenetrable, opaque, unintelligible) |
| clear as mud(expression, unfathomable, impenetrable, opaque, unintelligible) |
| cryptic(unfathomable, impenetrable, opaque, unintelligible, puzzling) |
| fathomless(unfathomable, impenetrable, opaque, unintelligible, puzzling) |
| inconceivable(unfathomable, impenetrable, opaque, unintelligible, puzzling) |
| mystifying(unfathomable, impenetrable, opaque, unintelligible, puzzling) |
| not understandable(expression, unfathomable, impenetrable, opaque, unintelligible) |
| opaque(unfathomable, impenetrable, unintelligible, puzzling) |
| perplexing(unfathomable, impenetrable, opaque, unintelligible, puzzling) |
| puzzling(unfathomable, impenetrable, opaque, unintelligible) |
| unclear(unfathomable, impenetrable, opaque, unintelligible, puzzling) |
| uncomprehensible(adjective, incomprehensible) |
| unimaginable(unfathomable, impenetrable, opaque, unintelligible, puzzling) |
| unknowable(unfathomable, impenetrable, opaque, unintelligible, puzzling) |
| incomprehensible(adjective, understandable) |