| unmerciful(adjective, hard, tough, harsh, cruel) |
| unreformed |
| unrelenting(adjective, hard, tough, harsh, cruel) |
| unremitting(adjective, hard, tough, harsh, cruel) |
| unrepenting(adjective, hard, tough, harsh, cruel) |
| unresponsive(adjective, hard, careless, indifferent, cruel) |
| unsoftened |
| unsusceptible(adjective, hard, careless, indifferent, cruel) |
| unsympathetic(adjective, hard, careless, indifferent, cruel) |
| untouched |
| unyielding(adjective, hard, tough, harsh, cruel) |
| vindictive(adjective, hard, tough, harsh, cruel) |
| accustomed(adjective, hard, unfeeling, unsympathetic, hardened) |
| be impenitent(expression, idiom, impenitence) |
| benumbed(adjective, hard, unfeeling, unsympathetic, hardened) |
| brazen |
| bullhead |
| casehardened(hard, unfeeling, unsympathetic, hardened, toughened) |
| cold-hearted(adjective, hard, cruel, unfeeling, unsympathetic) |
| coldblooded(careless, apathetic, unsympathetic, insensitive) |