| strange(adjective, obscure, unknown, clandestine, underground) |
| subjective |
| superhuman(abstract, theoretical, abstruse, philosophical) |
| supramundane(abstract, theoretical, abstruse, philosophical) |
| supranatural(abstract, theoretical, abstruse, philosophical) |
| surreptitious(adjective, secret, unknown, hidden, underground) |
| top-secret(clandestine, underground, undisclosed) |
| top secret(expression, clandestine, underground, undisclosed) |
| transcendental(strange, supernatural, abstract, spiritual, theoretical) |
| transmundane(obscure, deep, mysterious) |
| under wraps(expression, clandestine, underground, undisclosed) |
| undisclosed(obscure, dark, secret, unknown, hidden) |
| unearthly(obscure, deep, mysterious, abstract, theoretical) |
| weird(adjective, obscure, strange, deep, mysterious) |
| yogi |
| Delphian(adjective, evil, obscure, strange, deep) |
| abnormal |
| absolute |
| academic(sound, obscure, complex, knowledgeable, cultured) |
| accomplished(knowledgeable, cultured, educated, erudite, enlightened) |