| stiff(adjective, determined, resolute, persistent, obstinate) |
| unbendable(adjective, determined, resolute, obstinate, uncompromising) |
| unfailing(adjective, strong, firm, determined, steady) |
| wilful(adjective, determined, resolute, uncompromising, unshakeable) |
| adamantine(adjective, determined, resolute, uncompromising, unshakeable) |
| assiduous |
| bovine(adjective, determined, resolute, obstinate, uncompromising) |
| constant(adjective, strong, firm, determined, active) |
| energetic |
| hard(adjective, sharp, determined, resolute, stubborn) |
| indomitable(adjective, strong, tough, firm, difficult) |
| patient(adjective, strong, firm, energetic, determined) |
| perseverant |
| persisting(adjective, perseverance) |
| pig-headed(adjective, determined, resolute, obstinate, stubborn) |
| purposeful(adjective, deliberate, determined, resolute, obstinate) |
| resolved(adjective, deliberate, determined, fixed, resolute) |
| restive(adjective, determined, fixed, stubborn) |
| single-minded(adjective, tough, firm, determined, resolute) |
| strenuous |