| under wraps(expression, clandestine, underground, undisclosed) |
| undetected(adjective, obscure, dark, unknown, hidden) |
| unexplained(adjective, strange, new, remote, mysterious) |
| unexplored(adjective, strange, new, remote, mysterious) |
| unfamiliar(adjective, strange, new, remote, mysterious) |
| uninvestigated |
| unperceived(adjective, strange, new, remote, mysterious) |
| unpublished(adjective, obscure, unknown, clandestine, underground) |
| unseen(adjective, obscure, dark, secret, unknown) |
| viscerous(adjective, private, mental, inner) |
| spiritual(adjective, private, mental, inner) |
| supernatural(adjective, obscure, dark, superior, mysterious) |
| alien(adjective, strange, new, remote, mysterious) |
| anonymous(adjective, strange, indefinite, unidentified, nameless) |
| buried(adjective, latent) |
| cabalistic(adjective, obscure, deep, mysterious, weird) |
| censored |
| classified(adjective, obscure, unknown, clandestine, underground) |
| clouded(adjective, obscure, dark, unknown, hidden) |
| covered(adjective, obscure, secret, unknown, hidden) |