| abstruse(adjective, obscure, dark, mysterious, secret) |
| buried(adjective, obscure, dark, secret, unknown) |
| clandestine(adjective, obscure, dark, secret, unknown) |
| cloaked(secret, unknown, hidden, clandestine, concealed) |
| disguised(secret, unknown, hidden, clandestine, concealed) |
| dissembled(secret, hidden, clandestine, underground, underhanded) |
| hidden(adjective, secret, unknown, isolated, concealed) |
| in the dark(expression, idiom, unknown, hidden, concealed) |
| incog(secret, hidden, clandestine, underground, underhanded) |
| masked(secret, unknown, hidden, concealed, underhanded) |
| obscure(secret, unknown, isolated, hidden, concealed) |
| obscured(secret, hidden, clandestine, underground, concealed) |
| private(secret, unknown, isolated, hidden, clandestine) |
| screened(secret, unknown, isolated, hidden, concealed) |
| secluded(secret, unknown, isolated, hidden, concealed) |
| sequestered(secret, unknown, isolated, hidden, concealed) |
| sub rosa(expression, secret, clandestine, underground, underhanded) |
| ulterior(secret, unknown, hidden, concealed, underhanded) |
| under-the-table(secret, hidden, unknowing, clandestine, underground) |
| unsuspected(secret, hidden, clandestine, underground, underhanded) |