Incessant

прилагательное беспрестанный, непрекращающийся, непрерывный, непрестанный, постоянный Синоним(ы): persistent, unceasing, continual

Большой англо-русский словарь

Incessant

adjective Etymology: Middle English incessaunt, from Late Latin incessant-, incessans, from Latin in- + cessant-, cessans, present participle of cessare to delay — more at cease continuing or following without interruption; unceasing Synonyms: see continualincessantly adverb

Merriam-Webster's Collegiate Dictionary