| profound(adjective, hard, easy, obscure, difficult) |
| secret(adjective, evil, obscure, dark, strange) |
| difficult(adjective, hard, complex, complicated) |
| complicated(adjective, hard, evil, difficult, complex) |
| intricate(adjective, hard, evil, difficult, complex) |
| recondite(adjective, sound, easy, evil, sharp) |
| complex(adjective, hard, difficult) |
| occult(noun, adjective, evil, obscure, dark) |
| grave(adjective, hard, difficult, complex) |
| weighty(adjective, hard, difficult, complex) |
| involved(adjective, hard, difficult, complex) |
| knotty(adjective, hard, evil, difficult, complex) |
| labyrinthine(adjective, hard, difficult, complex) |
| obscure(adjective, dark, deep, mysterious, secret) |
| serious(adjective, hard, difficult, complex) |
| thorny(adjective, hard, difficult, complex) |
| tricky(adjective, hard, difficult, complex) |
| hard(adjective, difficult, complex) |
| nasty(adjective, hard, evil, difficult, complex) |
| private(adjective, obscure, individual, mysterious, secret) |