| unknown(adjective, obscure, strange, mysterious, private) |
| unexplored(adjective, strange, new, remote, mysterious) |
| unseen(adjective, hidden, ignored, imagined, overlooked) |
| undetected(adjective, knowledge, obscure, hidden, imaginary) |
| uncharted(adjective, strange, new, remote, mysterious) |
| unheard-of(adjective, obscure, strange, new, remote) |
| unfamiliar(adjective, obscure, strange, new, remote) |
| obscure(adjective, strange, unknown, unfamiliar, hidden) |
| unexposed(adjective, knowledge, obscure, untraveled, unfound) |
| strange(adjective, new, remote, mysterious, indefinite) |
| unnoticed(adjective, ignored) |
| remote(adjective, strange, new, mysterious, indefinite) |
| unbeknown |
| unexplained(adjective, strange, new, remote, mysterious) |
| unidentified(adjective, strange, new, remote, mysterious) |
| unrevealed(strange, new, remote, mysterious, indefinite) |
| untracked(adjective, latency implication) |
| mysterious(strange, new, remote, indefinite, unidentified) |
| unperceived(adjective, strange, new, remote, mysterious) |
| untraced(adjective, latency implication) |