| enigmatic(adjective, hard, obscure, solid, uncertain) |
| puzzling(adjective, hard, obscure, strange, uncertain) |
| ambiguous(adjective, obscure, uncertain, deep, vague) |
| cryptic(adjective, obscure, strange, uncertain, vague) |
| inscrutable(adjective, solid, strange, supernatural, dense) |
| obscure(adjective, hard, solid, uncertain, indefinite) |
| equivocal(obscure, strange, uncertain, vague, unclear) |
| mysterious(adjective, hard, obscure, delicate, solid) |
| abstruse(noun, hard, obscure, strange, uncertain) |
| confusing(adjective, hard, difficult, delicate, uncertain) |
| difficult(adjective, hard, strange, striking, tricky) |
| impenetrable(adjective, solid, strange, supernatural, dense) |
| indeterminate(adjective, obscure, uncertain, vague, unclear) |
| mystic(adjective, obscure, solid, secret, supernatural) |
| arcane(adjective, obscure, solid, strange, deep) |
| cabalistic(solid, strange, supernatural, dense, spiritual) |
| incomprehensible |
| oracular |
| perplexing(adjective, hard, difficult, strange, striking) |
| secret(adjective, strange, supernatural, hidden, spiritual) |