| undecipherable(adjective, unintelligibility) |
| ambiguous(adjective, mysterious, hidden, incoherent, unfathomable) |
| cabalistic(adjective, solid, strange, odd, mysterious) |
| inapprehensible(adjective, singular, unintelligibility) |
| inarticulate(adjective, vague, incoherent, incomprehensible, illegible) |
| incalculable(adjective, uncertain, unpredictable, unexpected) |
| incoherent(adjective, vague, incomprehensible, illegible, inarticulate) |
| indecipherable(adjective, deep, incoherent, unfathomable, profound) |
| insoluble(adjective, strange, unknown, curious, concealed) |
| numinous(adjective, obscure, dark, superior, mysterious) |
| puzzling(adjective, strange, unfathomable, impenetrable, opaque) |
| secret(adjective, obscure, dark, superior, strange) |
| uncertain(adjective, unpredictable, incoherent, unexpected, incomprehensible) |
| unexplained |
| ungraspable(adjective, solid, deep, dense, unfathomable) |
| unheard-of(adjective, extraordinary, strange, unbelievable, implausible) |
| unpredictable(adjective, uncertainty, uncertain, unexpected, inexpectation) |
| unrevealed(adjective, obscure, dark, superior, supernatural) |
| Delphic(adjective, solid, dense, unfathomable, impenetrable) |
| Greek(adjective, incoherent, unfathomable, incomprehensible, impenetrable) |