adjective

constant and unending.

the fort was subjected to ceaseless bombardment

continual,constant,continuous,incessant,unceasing,unending,endless,never-ending,interminable,non-stop,uninterrupted,unabated,unabating,unremitting,relentless,unrelenting,unrelieved,sustained,persistent,lasting,eternal,perpetual,unfaltering,unflagging,untiring,unwearied,unwavering,unswerving,undeviating,persevering,dogged,tireless,indefatigable