| impenetrable |
| cabalistic(adjective, evil, obscure, strange, deep) |
| complex(adjective, hard, fancy, obscure, difficult) |
| puzzling(adjective, hard, fancy, evil, obscure) |
| inscrutable(adjective, obscure, dark, uncertain, sophisticated) |
| perplexing(adjective, hard, fancy, obscure, difficult) |
| mystifying(adjective, evil, obscure, dark, strange) |
| subtle(adjective, sharp, obscure, exact, deep) |
| baffling |
| complicated(adjective, evil, obscure, difficult, heavy) |
| covert(adjective, strange, secret, hidden, concealed) |
| hard(adjective, fancy, obscure, difficult, intense) |
| inexplicable(adjective, dark, strange, uncertain, mysterious) |
| intricate(adjective, hard, fancy, evil, obscure) |
| involved(adjective, hard, fancy, obscure, difficult) |
| private(adjective, obscure, secret, unknown, hidden) |
| vague(adjective, unintelligibility) |
| abstract(adjective, obscure, intellectual, theoretical, abstruse) |
| academic(adjective, sound, obscure, complex, knowledgeable) |
| cabbalistic |