| tireless(adjective, set, strong, firm, energetic) |
| unswerving(adjective, close, strong, tough, correct) |
| bold(adjective, strong, tough, keen, firm) |
| undaunted(adjective, strong, determined, vigorous, noble) |
| decisive(adjective, set, firm, determined, significant) |
| set in stone(expression, adjective, idiom, calm, strong) |
| constant(adjective, calm, close, strong, secure) |
| dauntless(adjective, strong, tough, firm, energetic) |
| indefatigable(adjective, set, strong, firm, determined) |
| intrepid(adjective, strong, tough, firm, energetic) |
| standing pat(expression, adjective, tough, firm, determined) |
| unswayable(adjective, tough, firm, determined, distant) |
| plucky(adjective, clear, strong, tough, severe) |
| purposeful(adjective, strong, tough, keen, firm) |
| unflagging(adjective, strong, firm, solid, determined) |
| unshakeable(adjective, determined, uncompromising) |
| adamantine(adjective, hard, determined, rigid, strict) |
| indomitable(adjective, strong, tough, firm, determined) |
| stalwart(adjective, calm, strong, tough, firm) |
| strong(adjective, calm, tough, easy, flat) |