| unchangeable(adjective, strong, flat, certain, determined) |
| unhesitating(adjective, resolution, serious, resolute, persistent) |
| certain(adjective, determined, limited, definite, inflexible) |
| grim(adjective, mean, severe, harsh, cruel) |
| rigid(adjective, harsh, cruel, determined, fierce) |
| unchanging |
| confirmed(adjective, certain, limited, definite, inflexible) |
| contumacious(adjective, determined, fixed, persistent, obstinate) |
| dedicated(adjective, strong, firm, determined, steady) |
| devoted(adjective, strong, firm, determined, steady) |
| enduring(adjective, strong, flat, certain, determined) |
| gritty(adjective, determined, steady, resolution, bold) |
| headstrong(adjective, determined, fixed, resolute, stubborn) |
| insistent(adjective, resolute) |
| inveterate(adjective, certain, limited, definite, inflexible) |
| iron(adjective, resolution, persistent, obstinate, insistent) |
| merciless(adjective, mean, harsh, cruel, determined) |
| mortal(adjective, mean, severe, harsh, cruel) |
| obdurate(adjective, strong, flat, harsh, certain) |
| pertinacious(adjective, strong, firm, energetic, determined) |