| Rating | Solver | Clue |
|---|---|---|
| UNBREAKABLE | Ironclad | |
| NONNEGOTIABLE | Ironclad | |
| NON-NEGOTIABLE | Ironclad (3-10) | |
| IRON-CASED | Cased or covered with iron, as a vessel; ironclad. | |
| IRONCLAD | Rigorous; severe; exacting; as, an ironclad oath or pledge. | |
| MONITOR | An ironclad war vessel, very low in the water, and having one or more heavily-armored revolving turrets, carrying heavy guns. | |