| in ambush(expression, clandestine, underground, undisclosed) |
| incognito(clandestine, underground, undisclosed) |
| inside(clandestine, underground, undisclosed) |
| mystic(clandestine, underground, undisclosed) |
| mystical(clandestine, underground, undisclosed) |
| obscure(clandestine, underground, undisclosed) |
| off the record(expression, idiom, secret) |
| on the QT(expression, idiom, clandestine, underground, undisclosed) |
| out-of-the-way(clandestine, underground, undisclosed) |
| private(secret, clandestine, underground, undisclosed) |
| privileged |
| recondite(clandestine, underground, undisclosed) |
| reticent(clandestine, underground, undisclosed) |
| retired(clandestine, underground, undisclosed) |
| secluded(clandestine, underground, undisclosed) |
| secretive(clandestine, underground, undisclosed) |
| shrouded(clandestine, underground, undisclosed) |
| sly(clandestine, underground, undisclosed) |
| sneak(clandestine, underground, undisclosed) |
| sneaky(clandestine, underground, undisclosed) |