| dour |
| merciless(adjective, appearance, mean, hard, tough) |
| self-willed(adjective, tough, firm, determined, resolute) |
| unchangeable(adjective, strong, hard, steady, resolute) |
| unforgiving(adjective, mean, hard, tough, severe) |
| unswayable(adjective, determined, resolute, rigid, obstinate) |
| bigoted(adjective, determined, resolute, obstinate, uncompromising) |
| persevering(adjective, strong, tough, flat, firm) |
| set in stone(expression, adjective, idiom, set, mean) |
| brassbound(adjective, resist, determined, resolute, persistent) |
| bull-headed(adjective, determined, resolute, obstinate, stubborn) |
| contumacious(adjective, tough, firm, determined, fixed) |
| defiant(adjective, unwilling, resistant, opposed, undefeated) |
| die-hard(adjective, resist, determined, resolute, persistent) |
| indurate(adjective, set, mean, hard, firm) |
| pig-headed(adjective, determined, resolute, obstinate, stubborn) |
| pitiless(adjective, mean, hard, tough, severe) |
| sturdy(adjective, set, strong, hard, sound) |
| unfaltering(adjective, strong, firm, intense, certain) |
| unfeeling(adjective, mean, hard, severe, harsh) |