| indomitable(adjective, strong, firm, determined, steady) |
| inexhaustible(adjective, strong, firm, determined, steady) |
| intrepid |
| not discouraged(expression, adjective, bold, unconcerned, brave) |
| not put off(expression, adjective, idiom, bold, brave) |
| patient(adjective, strong, firm, determined, steady) |
| persistent(adjective, strong, firm, determined, steady) |
| pertinacious(adjective, strong, firm, determined, steady) |
| plodding(adjective, strong, firm, determined, steady) |
| plugging(adjective, strong, firm, determined, steady) |
| spunky |
| staunch(adjective, strong, firm, determined, steady) |
| steadfast(adjective, bold, unconcerned, brave, carefree) |
| steady(adjective, strong, firm, determined, constant) |
| strong(adjective, firm, determined, steady, constant) |
| tenacious(adjective, strong, firm, determined, steady) |
| tireless(adjective, strong, firm, determined, steady) |
| unafraid(adjective, bold, unconcerned, brave, steadfast) |
| unalarmed(adjective, bold, unconcerned, brave, steadfast) |
| unapprehensive(adjective, bold, unconcerned, brave, steadfast) |