| stubborn(adjective, characteristic, quality, tough, resist) |
| uncompromising(adjective, tough, resist, determined, resolute) |
| inflexible(adjective, resist, determined, resolute, obstinate) |
| inexorable(adjective, tough, resist, determined, resolute) |
| rigid(adjective, tough, severe, resist, determined) |
| unrelenting(adjective, tough, resist, determined, resolute) |
| unyielding(adjective, resist, determined, resolute, obstinate) |
| obdurate(adjective, resist, determined, resolute, inflexible) |
| unbending(adjective, resist, determined, resolute, persistent) |
| determined(adjective, tough, resolute, obstinate, stubborn) |
| resolute(adjective, determined, rigid, obstinate, stubborn) |
| relentless(adjective, resist, determined, resolute, obstinate) |
| immovable(adjective, determined, fixed, resolute, obstinate) |
| firm(adjective, determined, resolute, obstinate, stubborn) |
| adamant(adjective, resist, determined, resolute, inflexible) |
| insistent(adjective, determined, resolute, obstinate, uncompromising) |
| stiff(adjective, severe, determined, resolute, obstinate) |
| adamantine(adjective, resist, determined, resolute, obstinate) |
| fixed(adjective, tough, determined, resolute, obstinate) |
| unshakable(adjective, determined, resolute, obstinate, uncompromising) |