| intransigent(adjective, tough, severe, determined, resolute) |
| persevering(adjective, tough, firm, determined, unreasonable) |
| refractory(adjective, tough, firm, difficult, determined) |
| stern(adjective, determined, serious, resolute, uncompromising) |
| strong-willed(adjective, resolute, tenacious) |
| tough(adjective, strong, hard, firm, difficult) |
| unrelenting(adjective, strong, hard, tough, firm) |
| bold(adjective, resolute, tenacious) |
| bullet-headed |
| deaf(adjective, indifferent, unresponsive, oblivious, unwilling) |
| doctrinaire(adjective, opinionated, dogmatic) |
| hard-nosed(adjective, strong, hard, tough, determined) |
| implacable(adjective, strong, hard, tough, firm) |
| inexorable(adjective, strong, hard, tough, determined) |
| inflexible(adjective, strong, hard, tough, firm) |
| relentless(adjective, strong, hard, tough, determined) |
| resolute(adjective, resolute, tenacious) |
| self-willed(tough, firm, difficult, determined, awkward) |
| set(adjective, resolute) |
| unbending(adjective, strong, hard, tough, firm) |