| indefatigable(adjective, activity, strong, continue, firm) |
| tireless(adjective, strong, continue, firm, energetic) |
| untiring(adjective, continue, determined, tired, perseverance) |
| unflagging(adjective, strong, continue, firm, energetic) |
| untired(adjective, refreshment) |
| unfailing(adjective, strong, continue, firm, energetic) |
| unwearying(adjective, tireless) |
| weariless(adjective, continue, tired, tireless) |
| industrious(adjective, activity, tireless) |
| inexhaustible(adjective, strong, continue, firm, energetic) |
| persevering(adjective, strong, firm, energetic, determined) |
| assiduous(adjective, activity) |
| energetic(adjective, good, clear, pleasant, bright) |
| resolute(adjective, strong, firm, energetic, determined) |
| sedulous(adjective, activity) |
| diligent(adjective, activity) |
| indomitable(adjective, strong, firm, determined, steady) |
| steadfast(adjective, tireless) |
| unfaltering(adjective, strong, firm, energetic, determined) |
| active(adjective, good, clear, pleasant, bright) |