| fixed(adjective, mean, hard, firm, determined) |
| set(adjective, severe, determined, resolute, obstinate) |
| harsh(adjective, mean, strong, hard, tough) |
| obstinate(adjective, mean, strong, hard, tough) |
| persistent(adjective, tough, firm, certain, determined) |
| stern(adjective, appearance, mean, tough, severe) |
| unshakable(adjective, mean, hard, tough, certain) |
| hard(adjective, mean, strong, tough, severe) |
| remorseless(adjective, animal, mean, tough, severe) |
| steadfast(adjective, certain, determined, resolute, persistent) |
| unwavering(adjective, determined, resolute, rigid, obstinate) |
| unbendable(adjective, resist, determined, resolute, persistent) |
| cruel(adjective, appearance, mean, strong, hard) |
| hard-nosed(adjective, mean, strong, hard, tough) |
| unforgiving(adjective, mean, hard, tough, severe) |
| severe(adjective, appearance, mean, strong, hard) |
| unappeasable(adjective, mean, severe, harsh, cruel) |
| unremitting(adjective, hard, tough, harsh, determined) |
| dogged(adjective, appearance, mean, hard, tough) |
| ruthless(adjective, animal, appearance, mean, hard) |