| Solution | Length | |
|---|---|---|
| 4 letters | ||
| atan | 4 | |
| 6 letters | ||
| untold | 6 | |
| agenda | 6 | |
| abduct | 6 | |
| unseen | 6 | |
| hidden | 6 | |
| sealed | 6 | |
| secret | 6 | |
| virgin | 6 | |
| 7 letters | ||
| private | 7 | |
| STIFLED | 7 | |
| unknown | 7 | |
| strange | 7 | |
| 8 letters | ||
| currency | 8 | |
| unspoken | 8 | |
| puzzling | 8 | |
| ulterior | 8 | |
| sneaking | 8 | |
| 9 letters | ||
| unbeknown | 9 | |
| unuttered | 9 | |
| uncharted | 9 | |
| UNEXPOSED | 9 | |
| untouched | 9 | |
| unplumbed | 9 | |
| smothered | 9 | |
| 10 letters | ||
| UNEXPLORED | 10 | |
| unrevealed | 10 | |
| unfathomed | 10 | |
| restricted | 10 | |
| UNKNOWABLE | 10 | |
| top-secret | 10 | |
| unfamiliar | 10 | |
| unheard-of | 10 | |
| SUPPRESSED | 10 | |
| 11 letters | ||
| UNEXPLAINED | 11 | |
| unsuspected | 11 | |
| UNDER WRAPS | 11 | |
| unutterable | 11 | |
| UNPERCEIVED | 11 | |
| 12 letters | ||
| confidential | 12 | |
| UNIDENTIFIED | 12 | |
| UNDISCOVERED | 12 | |
| unclassified | 12 | |
| 13 letters | ||
| undisclosable | 13 | |
| 14 letters | ||
| undiscoverable | 14 | |
| 15 letters | ||
| thesecretgarden | 15 | |