| problematic(adjective, open, uncertain, doubtful, dubious) |
| deep(adjective, hard, evil, heavy, loose) |
| doubtful(adjective, uncertain, vague, dubious, mysterious) |
| hidden(adjective, cover, hard, evil, obscure) |
| indeterminate(adjective, obscure, uncertain, doubtful, vague) |
| knotty(adjective, hard, evil, obscure, difficult) |
| problematical(adjective, hard, obscure, uncertainty, uncertain) |
| unintelligible(adjective, hard, obscure, rough, difficult) |
| Delphic |
| difficult(adjective, hard, obscure, dark, strange) |
| fine(adjective, exact, discriminating) |
| indistinct(uncertain, vague, unclear, indistinguishable) |
| mystical(adjective, hard, knowledge, evil, obscure) |
| sphinxlike(adjective, obscure, dark, strange, odd) |
| unknowable(adjective, obscure, solid, strange, odd) |
| unreadable(adjective, unfathomable, unintelligible, sphinx-like) |
| close(solid, mysterious, private, reticent, dense) |
| complicated(adjective, hard, evil, obscure, difficult) |
| dubious(uncertain, doubtful, vague, unclear, tricky) |
| hard(obscure, difficult, solid, unclear, dense) |