| stony(adjective, firm, stiff, rigid) |
| solid(adjective, hard, firm, stiff, compact) |
| granitic |
| hard(adjective, strong, firm, substantial, stiff) |
| rocky(adjective, firm, difficult, stiff, rigid) |
| granitelike |
| tough(adjective, firm, difficult, stiff, rigid) |
| firm(adjective, strong, hard, substantial, stiff) |
| flinty |
| obdurate |
| unyielding(adjective, hard, firm, stiff, compact) |
| concrete(adjective, strong, hard, substantial, sturdy) |
| dense(adjective, strong, hard, firm, substantial) |
| inflexible(adjective, firm, stiff, rigid, unyielding) |
| rigid(adjective, firm, stiff) |
| steely |
| stiff(adjective, firm, rigid) |
| adamantine(adjective, firm, stiff, rigid) |
| callous(adjective, firm, stiff, rigid) |
| certain(adjective, true, reliable, trustworthy, loyal) |