| petrified(adjective, firm, solid, hardened) |
| poured(adjective, firm, solid, hardened) |
| precast(adjective, firm, solid, hardened) |
| set in stone(expression, adjective, idiom, firm) |
| steeled(adjective, firm, solid, hardened) |
| stiff(adjective, hard, firm, solid) |
| strong(adjective, hard, firm, solid) |
| syrupy(adjective, solid, heavy, deep) |
| thickened(verb, adjective, solid, heavy) |
| turbid(adjective, solid, heavy, deep) |
| unyielding(adjective, hard, firm, solid) |
| vitrified(adjective, solid, heavy, deep) |
| adamantine(adjective, strong, hard, firm) |
| callous(adjective, strong, hard, firm) |
| hard-handed(adjective, strong, hard, compact) |
| hard as nails(expression, adjective, idiom, strong) |
| indurated(adjective, strong, hard, firm) |
| inflexible(adjective, strong, hard, firm) |
| iron(adjective, strong, hard, firm) |
| rigid(adjective, strong, hard, firm) |