| hardened(adjective, hard, cold, cruel, pitiless) |
| incompliant(adjective, resist, determined, resolute, persistent) |
| uncharitable(adjective, heartless, terrible behavior) |
| uncompliant(adjective, resist, determined, resolute, persistent) |
| brassbound(adjective, resist, determined, resolute, persistent) |
| die-hard(adjective, resist, determined, resolute, persistent) |
| inhumane(adjective, animal, mean, hard, severe) |
| iron(adjective, resist, determined, resolute, persistent) |
| murderous(adjective, hard, harsh, violent, cruel) |
| tough |
| unbendable(adjective, resist, determined, resolute, persistent) |
| unremitting(adjective, hard, cruel, persistent, constant) |
| unsympathetic(adjective, animal, mean, hard, harsh) |
| rigorous(adjective, hard, harsh, cruel, determined) |
| sadistic(adjective, mean, harsh, violent, cruel) |
| severe(adjective, mean, harsh, cruel, vicious) |
| unashamed |
| uncompassionate(adjective, animal, mean, hard, cold) |
| unkind(adjective, animal, mean, hard, severe) |
| unsparing(adjective, severe, harsh, cruel, persistent) |