| Solution | Length | |
|---|---|---|
| 3 letters | ||
| set | 3 | |
| 4 letters | ||
| fast | 4 | |
| firm | 4 | |
| true | 4 | |
| 5 letters | ||
| fixed | 5 | |
| stone | 5 | |
| stiff | 5 | |
| rigid | 5 | |
| stern | 5 | |
| stoic | 5 | |
| 6 letters | ||
| steely | 6 | |
| rooted | 6 | |
| secure | 6 | |
| static | 6 | |
| steady | 6 | |
| 7 letters | ||
| riveted | 7 | |
| staunch | 7 | |
| regular | 7 | |
| settled | 7 | |
| adamant | 7 | |
| unmoved | 7 | |
| 8 letters | ||
| unshaken | 8 | |
| UNLOVING | 8 | |
| standpat | 8 | |
| stubborn | 8 | |
| rigorous | 8 | |
| ungiving | 8 | |
| SOULLESS | 8 | |
| 9 letters | ||
| unfeeling | 9 | |
| unpliable | 9 | |
| steadfast | 9 | |
| fastfleet | 9 | |
| tenacious | 9 | |
| unmovable | 9 | |
| resistant | 9 | |
| unbending | 9 | |
| 10 letters | ||
| stationary | 10 | |
| UNYIELDING | 10 | |
| UNAFFECTED | 10 | |
| relentless | 10 | |
| spiritless | 10 | |
| UNSWERVING | 10 | |
| 11 letters | ||
| ESTABLISHED | 11 | |
| IMPREGNABLE | 11 | |
| unalterable | 11 | |
| unrelenting | 11 | |
| UNTOUCHABLE | 11 | |
| unemotional | 11 | |
| UNFLAPPABLE | 11 | |
| 12 letters | ||
| UNCHANGEABLE | 12 | |
| unresponsive | 12 | |
| recalcitrant | 12 | |
| 13 letters | ||
| unsympathetic | 13 | |
| unimpassioned | 13 | |
| unsusceptible | 13 | |
| 14 letters | ||
| unaffectionate | 14 | |
| UNCOMPROMISING | 14 | |