| bestial(adjective, animal, mean, severe, harsh) |
| bloodthirsty(adjective, severe, harsh, cruel) |
| cold-hearted(adjective, hard, cold, cruel, negative) |
| compassionless |
| dog-eat-dog(adjective, mean, hard, severe, harsh) |
| dogged(adjective, tough, firm, harsh, cruel) |
| fell(adjective, animal, mean, harsh, violent) |
| feral(adjective, mean, severe, harsh, violent) |
| hardhearted(adjective, mean, hard, harsh, cold) |
| inclement(adjective, cruel, brutal, unkind, strict) |
| indurate(adjective, determined, resolute, uncompromising, unshakeable) |
| intractable(adjective, tough, firm, cruel, unreasonable) |
| mortal(adjective, mean, severe, harsh, cruel) |
| rancorous(adjective, mean, harsh, cruel, vicious) |
| single-minded(adjective, tough, firm, harsh, cruel) |
| sour |
| steadfast(adjective, determined, resolute, uncompromising, unshakeable) |
| tyrannical |
| unregenerate |
| unswerving(adjective, determined, resolute, uncompromising, unshakeable) |