| relentless(adjective, continue, steady, persistent, constant) |
| steady(adjective, regular, persistent, even, constant) |
| nonstop(adjective, direct, continue, steady, regular) |
| perennial(adjective, persistent, constant, continuous, enduring) |
| undying(adjective, constant, continuous, endless, infinite) |
| continuing(adjective, certain, persistent, constant, reliable) |
| lasting(adjective, certain, persistent, constant, reliable) |
| regular(verb, adjective, sound, steady, persistent) |
| unchanging(adjective, certain, steady, persistent, constant) |
| amaranthine(adjective, continue, constant, abundant, endless) |
| dateless |
| deathless(adjective, constant, abundant, endless, indefinite) |
| enduring(adjective, certain, steady, persistent, constant) |
| infinite(adjective, constant, abundant, unrestrained, endless) |
| unvarying(adjective, steady, regular, persistent, even) |
| monotonous(adjective, dull, boring, persistent, constant) |
| recurrent(adjective, steady, persistent, constant, continuous) |
| repeated(adjective, continuous) |
| repetitive(adjective, continuous, repetitious) |
| round-the-clock(adjective, continue, continual) |