adj. 25B6; adjective
deep caves in perpetual darkness : EVERLASTING, never-ending, eternal, permanent, unending, endless, without end, lasting, long-lasting, constant, abiding, enduring, perennial, timeless, ageless, deathless, undying, immortal; unfailing, unchanging, never-changing, changeless, unfading; poetic/literary sempiternal, perdurable.
a perpetual state of fear : CONSTANT, permanent, uninterrupted, continuous, unremitting, unending, unceasing, persistent, unbroken.
her mother's perpetual nagging : INTERMINABLE, incessant, ceaseless, endless, without respite, relentless, unrelenting, persistent, continual, continuous, non-stop, never-ending, recurrent, repeated, unremitting, sustained, round-the-clock, unabating; informal eternal.
temporary, intermittent.