| private(secret, hidden, clandestine, underground, undisclosed) |
| restricted(clandestine, underground, discreet, undisclosed) |
| secreted |
| secretive(restricted, clandestine, underground, discreet, undisclosed) |
| shamed |
| shrouded(verb, secret, hidden, clandestine, underground) |
| simulated |
| sly(adjective, clandestine, underground, undisclosed) |
| sneak(close, restricted, clandestine, underground, discreet) |
| sneaky(adjective, clandestine, underground, undisclosed) |
| stealthy(adjective, secret, hidden, clandestine, underground) |
| sub-rosa(close, clandestine, underground, undisclosed, furtive) |
| surreptitious(secret, hidden, clandestine, underground, undisclosed) |
| top secret(expression, close, clandestine, underground, undisclosed) |
| treacherous(adjective, dangerous) |
| unacknowledged(close, clandestine, underground, undisclosed, furtive) |
| under-the-table(secret, hidden, clandestine, underground, undisclosed) |
| under false pretense(expression, idiom, close, clandestine, underground) |
| undercover(secret, hidden, clandestine, underground, undisclosed) |
| underhand(secret, hidden, clandestine, underground, undisclosed) |