| stony-hearted |
| strict(adjective, set, strong, hard, tough) |
| thorough(adjective, resolute) |
| true(adjective, resolute) |
| unremitting(adjective, hard, tough, harsh, grim) |
| unsparing(adjective, mean, strong, hard, tough) |
| unstoppable(adjective, harsh, cruel, determined, fierce) |
| unswerving(adjective, determined, resolute, uncompromising, unshakeable) |
| vicious(adjective, mean, evil, nasty, harsh) |
| vindicatory |
| willful(adjective, determined, resolute, uncompromising, unshakeable) |
| astringent(adjective, strong, hard, tough, severe) |
| austere(adjective, appearance, mean, strong, hard) |
| authoritarian(adjective, strong, hard, tough, severe) |
| avaricious(adjective, hard, tough, harsh, cruel) |
| bestial(adjective, animal, mean, severe, evil) |
| bloodthirsty(adjective, severe, evil, nasty, harsh) |
| bloody(adjective, hard, tough, harsh, cruel) |
| bound(adjective, harsh, cruel, determined, fierce) |
| bound and determined(expression, adjective, idiom, harsh, cruel) |