| unstoppable(adjective, harsh, cruel, determined, fierce) |
| absolute(adjective, severity, uncompromising) |
| certain(adjective, near, obvious, coming, intended) |
| dogmatic(fixed, rigid, inflexible, uncompromising, intolerant) |
| dour(adjective, severity) |
| exacting(adjective, persistent, severity, obstinate, insistent) |
| fated(adjective, certain, obvious, expected, necessary) |
| inclement(severity, pitilessness) |
| indurate(adjective, mean, hard, determined, resolute) |
| iron-willed(adjective, determined, resolute, uncompromising, unshakeable) |
| persevering(adjective, tough, firm, determined, unreasonable) |
| pertinacious(adjective, tough, determined, resolute, obstinate) |
| rock-ribbed(adjective, determined, resolute, uncompromising, unshakeable) |
| stony(adjective, mean, hard, harsh, cold) |
| unalterable(adjective, hard, severe, stiff, inflexible) |
| uncontrollable(strong, necessity, overwhelming, disorderly, boisterous) |
| unfeeling(adjective, mean, hard, severe, evil) |
| unmerciful(adjective, mean, hard, tough, severe) |
| unswerving(adjective, intense, determined, resolute, persistent) |
| unsympathetic(adjective, mean, hard, severe, harsh) |