| indurate(adjective, firm, solid, determined, resolute) |
| obstreperous |
| opinionated(adjective, stubborn) |
| persistent(adjective, stubborn) |
| pigheaded(adjective, tough, firm, difficult, awkward) |
| resolute(adjective, tough, firm, difficult, determined) |
| steadfast(adjective, determined, resolute, stubborn, uncompromising) |
| steely(adjective, firm, solid, determined, resolute) |
| stiff(adjective, hard, tough, severe, firm) |
| stiff-necked(adjective, determined, resolute, stubborn, uncompromising) |
| ungovernable(adjective, tough, difficult, wild, awkward) |
| unmanageable(adjective, tough, firm, difficult, wild) |
| wayward(adjective, tough, difficult, wild, awkward) |
| willful(adjective, tough, firm, difficult, awkward) |
| balky(adjective, stubborn) |
| dogged(adjective, stubborn) |
| hard(adjective, severe, firm, solid, stiff) |
| immovable(adjective, difficult, determined, resolute, stubborn) |
| indomitable(adjective, tough, difficult, wild, awkward) |
| inelastic(adjective, hard, tough, severe, firm) |