| proved(adjective, confirmed) |
| rash(determined, impulsive, stubborn, reckless, heedless) |
| recalcitrant(adjective, persistent, obstinate, insistent, dogged) |
| reckless(determined, impulsive, stubborn, heedless, impetuous) |
| resolved(adjective, persistent, obstinate, insistent, dogged) |
| rough(adjective, strong, hard, tough, severe) |
| seasoned(adjective, confirmed) |
| self-willed(determined, impulsive, stubborn, reckless, impetuous) |
| serious(adjective, strong, hard, tough, severe) |
| single-minded(adjective, persistent, obstinate, insistent, dogged) |
| staid(adjective, confirmed) |
| steadfast(adjective, persistent, obstinate, insistent, dogged) |
| steely(adjective, strong, hard, tough, severe) |
| stiff-necked(adjective, strong, hard, tough, severe) |
| stouthearted(adjective, persistent, obstinate, insistent, dogged) |
| strong-minded(determined, impulsive, stubborn, reckless, impetuous) |
| tenacious(adjective, persistent, obstinate, insistent, dogged) |
| tough(adjective, strong, hard, severe, harsh) |
| unconquerable(adjective, persistent, obstinate, insistent, dogged) |
| uncontrollable(determined, impulsive, stubborn, reckless, heedless) |