| hard-headed |
| resolute(adjective, tough, determined, usual, regular) |
| balky(tough, firm, unreasonable, grim, inflexible) |
| disobedient |
| inexorable(adjective, mean, hard, tough, determined) |
| persevering(adjective, tough, firm, determined, unreasonable) |
| persistent(adjective, tough, firm, determined, unreasonable) |
| relentless(adjective, mean, hard, tough, determined) |
| restive(adjective, determined, fixed, stubborn) |
| uncooperative(adjective, mean, hard, tough, difficult) |
| firm(adjective, mean, hard, tough, determined) |
| fixed(adjective, mean, hard, tough, firm) |
| hard-nosed(adjective, mean, hard, tough, determined) |
| implacable(adjective, mean, hard, tough, firm) |
| insistent(adjective, stubborn) |
| pat(adjective, determined, usual, regular, resolute) |
| rebellious(adjective, tough, firm, unreasonable, grim) |
| steadfast(adjective, tough, firm, determined, usual) |
| strong-willed |
| ungovernable(adjective, tough, difficult, awkward, impulsive) |