| stubborn(adjective, characteristic, quality, tough, resist) |
| rigid(adjective, tough, severe, firm, resist) |
| unyielding(adjective, tough, firm, solid, resist) |
| inflexible(adjective, tough, firm, solid, resist) |
| obdurate(adjective, resist, determined, resolute, obstinate) |
| unbending(adjective, firm, resist, determined, resolute) |
| uncompromising(adjective, tough, firm, resist, determined) |
| intransigent(adjective, resist, determined, resolute, obstinate) |
| inexorable(adjective, tough, firm, resist, determined) |
| unrelenting(adjective, resist, determined, resolute, persistent) |
| insubordinate(adjective, stubborn) |
| uncompliant(adjective, resist, determined, resolute, persistent) |
| adamantine(adjective, resist, determined, resolute, persistent) |
| intractable(adjective, tough, firm, difficult, unreasonable) |
| refractory(adjective, hard, tough, firm, difficult) |
| unbendable(adjective, firm, resist, determined, resolute) |
| brassbound(adjective, resist, determined, resolute, persistent) |
| die-hard(adjective, resist, determined, resolute, persistent) |
| firm(adjective, tough, solid, determined, stiff) |
| grim(adjective, resist, determined, resolute, persistent) |