| undiscovered(strange, remote, mysterious, indefinite) |
| undistinguished(strange, remote, indefinite, unidentified) |
| unexplained(strange, remote, mysterious, indefinite) |
| unidentified(strange, remote, mysterious, indefinite) |
| unnoted(strange, remote, indefinite, unidentified) |
| unorthodox(adjective, unusual, strange, special) |
| unperceived(strange, remote, mysterious, indefinite) |
| unrecognized(strange, remote, mysterious, indefinite) |
| unrenowned(strange, remote, mysterious, indefinite) |
| unrevealed(strange, remote, mysterious, indefinite) |
| unsung(strange, remote, indefinite, unidentified) |
| untold(strange, remote, mysterious, indefinite) |
| X(strange, remote, mysterious, indefinite) |
| out of the ordinary(expression, adjective, idiom, strange) |
| prodigious(unusual, exceptional, special, fantastic) |
| recondite(unknown, untried) |
| surprising(unusual, strange, special, rare) |
| uninvestigated(unknown, untried) |
| untried(unusual, strange, mysterious, unknown) |