| inflexible(adjective, hard, stiff, rigid) |
| rigid(adjective, hard, stiff, resolute) |
| obstinate(adjective, hard, stiff, rigid) |
| fixed(adjective, hard, stiff, rigid) |
| uncompliant(adjective, hard, stiff, rigid) |
| uncompromising(adjective, hard, stiff, rigid) |
| dogged(adjective, hard, stiff, rigid) |
| hard(adjective, stiff, resolute, rigid) |
| immutable(adjective, hard, stiff, rigid) |
| intractable(adjective, hard, stiff, rigid) |
| stiff(adjective, hard, resolute, rigid) |
| unchangeable(adjective, hard, stiff, rigid) |
| unyielding(adjective, hard, stiff, rigid) |
| hard-and-fast(adjective, hard, stiff, rigid) |
| iron(adjective, hard, stiff, rigid) |
| single-minded(adjective, hard, stiff, rigid) |
| staunch(adjective, hard, stiff, rigid) |
| steadfast(adjective, hard, stiff, rigid) |
| steely(adjective, hard, stiff, rigid) |
| stringent(adjective, hard, stiff, rigid) |