| determined(adjective, good, strong, firm, honest) |
| firm(adjective, good, set, clear, strong) |
| secure(adjective, open, solid, certain, true) |
| unceasing(adjective, strong, continue, firm, determined) |
| assiduous(adjective, certain, unchanging) |
| ceaseless(adjective, continue, certain, unchanging) |
| continuing(adjective, strong, firm, certain, determined) |
| diligent(adjective, certain, unchanging) |
| endless(adjective, continue, certain, steady, constant) |
| persevering(adjective, set, strong, firm, energetic) |
| pertinacious(adjective, strong, firm, determined, steady) |
| relentless(adjective, continue) |
| solid(adjective, good, strong, open, certain) |
| sound(adjective, strong, solid, steady, consistent) |
| stubborn |
| tenacious(adjective, strong, firm, determined, steady) |
| uninterrupted(adjective, continue) |
| unrelenting(adjective, certain, unchanging) |
| unvarying(adjective, certain, steady, regular, definite) |
| weariless(adjective, continue, tired, tireless) |