Synonyms and related words :
abiding, age-long, aged, ancient, antique, articulated, assiduous, catenated, ceaseless, changeless, chronic, concatenated, connected, constant, continual, continued, continuous, cyclical, diligent, direct, diuturnal, dogged, durable, endless, enduring, evergreen, faithful, featureless, firm, fixed, frozen, gapless, hardy, immediate, immobile, immutable, inalterable, incessant, indefatigable, indomitable, industrious, insistent, intact, interminable, intransient, inveterate, invincible, inviolate, joined, jointless, lasting, lifelong, linked, long-lasting, long-lived, long-standing, long-term, longeval, longevous, loyal, macrobiotic, monotonous, never-ending, never-tiring, nonstop, obstinate, of long duration, of long standing, old, patient, patient as Job, perdurable, perduring, perennial, periodic, permanent, perpetual, perseverant, persevering, persistent, persisting, pertinacious, plodding, plugging, preoccupied, quiescent, rapt, recurrent, relentless, remaining, repetitive, resolute, rigid, round-the-clock, running, seamless, sedulous, sempervirent, serried, single-minded, sleepless, slogging, smooth, solid, stable, static, stationary, staying, steadfast, steady, sticking, straight, stubborn, sustained, tenacious, tireless, torpid, tough, twenty-four-hour, unabating, unaltered, unbroken, unceasing, unchangeable, unchanged, unchanging, unchecked, unconquerable, undaunted, undestroyed, undifferentiated, undiscouraged, undrooping, undying, unending, unfading, unfailing, unfaltering, unflagging, unflinching, uniform, unintermitted, unintermittent, unintermitting, uninterrupted, unnodding, unrelaxing, unrelenting, unrelieved, unremitting, unshifting, unsleeping, unstopped, unswerving, untiring, unvaried, unvarying, unwavering, unwearied, unwearying, unwinking, utterly attentive, vital, weariless,