| cruel(adjective, appearance, mean, strong, hard) |
| unappeasable(adjective, mean, severe, harsh, cruel) |
| hard(adjective, mean, strong, tough, severe) |
| pitiless(adjective, animal, mean, hard, tough) |
| iron(adjective, mean, strong, hard, tough) |
| resolute(adjective, hard, firm, determined, resolute) |
| steadfast(adjective, tough, firm, determined, resolute) |
| obstinate(adjective, mean, hard, cruel, determined) |
| firm(adjective, mean, strong, hard, tough) |
| inhuman(adjective, animal, mean, hard, tough) |
| mortal(adjective, mean, severe, harsh, cruel) |
| steely(adjective, strong, hard, tough, determined) |
| vindictive(adjective, mean, hard, tough, severe) |
| determined(adjective, strong, hard, tough, harsh) |
| dogged(adjective, appearance, mean, hard, tough) |
| immovable(adjective, mean, strong, hard, tough) |
| stiff-necked(adjective, mean, strong, hard, tough) |
| uncompliant(adjective, tough, firm, resist, determined) |
| unfeeling(adjective, animal, mean, hard, severe) |
| incompliant(adjective, resist, determined, resolute, persistent) |