| constant(adjective, strong, sound, continue, firm) |
| perpetual(adjective, sound, continue, determined, steady) |
| continual(adjective, continue, determined, regular, normal) |
| unceasing(adjective, strong, continue, firm, determined) |
| unremitting(adjective, strong, sound, continue, firm) |
| continuous(adjective, sound, continue, firm, steady) |
| ceaseless(adjective, sound, continue, steady, regular) |
| uninterrupted(adjective, sound, continue, steady, regular) |
| endless(verb, adjective, sound, continue, determined) |
| persistent(adjective, strong, continue, firm, determined) |
| interminable(adjective, continue, determined, steady, persistent) |
| unending(adjective, continue, steady, stable, persistent) |
| eternal(adjective, continue, pause, steady, regular) |
| everlasting(adjective, continue, steady, persistent, constant) |
| unbroken(verb, adjective, sound, steady, regular) |
| never-ending(adjective, determined, steady, regular, persistent) |
| non-stop(adjective, continual) |
| steady(adjective, strong, firm, determined, regular) |
| nonstop(adjective, direct, continue, steady, regular) |
| relentless(adjective, continue, determined, steady, persistent) |