| persistent(adjective, tough, firm, determined, obstinate) |
| relentless(adjective, appearance, strong, tough, firm) |
| restive(adjective, determined, negative, hostile, fixed) |
| set(adjective, persistent, strict, obstinate, stubborn) |
| stiff-necked(adjective, tough, firm, stupid, unreasonable) |
| tenacious(adjective, tough, firm, difficult, persistent) |
| uncompliant(adjective, tough, firm, unreasonable, irritable) |
| unregenerate(adjective, persistent, obstinate, insistent, dogged) |
| unrelenting(adjective, appearance, strong, tough, firm) |
| bloody-minded(adjective, persistent, obstinate, insistent, dogged) |
| fixed(adjective, hard, tough, rough, firm) |
| incompliant(adjective, tough, firm, difficult, unreasonable) |
| lawless(adjective, control, order, resist, violent) |
| merciless(adjective, appearance, hard, severe, rough) |
| narrow-minded(adjective, persistent, obstinate, insistent, dogged) |
| stern(adjective, appearance, terrible, persistent, obstinate) |
| unchangeable(adjective, set, hard, stiff, rigid) |
| balky(adjective, tough, firm, negative, hostile) |
| cussed(tough, firm, persistent, obstinate, stubborn) |
| grim(adjective, appearance, tough, firm, cruel) |