| inflexible(adjective, hard, tough, firm, solid) |
| unyielding(adjective, hard, tough, firm, solid) |
| rigid(adjective, hard, tough, severe, firm) |
| stiff(adjective, hard, tough, firm, solid) |
| firm(noun, adjective, hard, tough, solid) |
| unbending(adjective, firm, determined, stiff, resolute) |
| uncompromising(adjective, tough, firm, determined, distant) |
| hard(adjective, tough, severe, firm, harsh) |
| stubborn(adjective, determined, resolute, obstinate, uncompromising) |
| obstinate(adjective, determined, resolute, obstinate, uncompromising) |
| resolute(adjective, tough, firm, determined, distant) |
| brittle(adjective, hard, firm, solid, tense) |
| immovable(adjective, determined, resolute, obstinate, uncompromising) |
| obdurate(adjective, determined, resolute, obstinate, uncompromising) |
| unbendable(adjective, firm, determined, resolute, rigid) |
| adamant(adjective, determined, resolute, obstinate, uncompromising) |
| inexorable(adjective, tough, firm, determined, stiff) |
| tough(adjective, hard, determined, resolute, rigid) |
| bovine(adjective, determined, resolute, obstinate, uncompromising) |
| crisp(adjective, hard, tough, firm, stiff) |