Synonyms and related words :
abiding, ageless, ardent, articulated, assiduous, catenated, ceaseless, changeless, chattering, coeternal, concatenated, connected, constant, continual, continued, continuing, continuous, cyclical, dateless, diligent, direct, dogged, endless, enduring, energetic, eternal, eterne, ever-being, ever-durable, ever-during, everlasting, everliving, faithful, featureless, fervent, gapless, hard, hardworking, immediate, immemorial, immutable, inalterable, incessant, incommutable, inconvertible, indefatigable, indefeasible, indestructible, indomitable, industrious, inert, infinite, insistent, insusceptible of change, interminable, intransmutable, invariable, invincible, irretrievable, irreversible, irrevocable, joined, jointless, laborious, lasting, linked, loyal, machine gun, monotonous, never idle, never-ceasing, never-ending, never-tiring, noble, nonreturnable, nonreversible, nonstop, nonterminating, nonterminous, obstinate, olamic, oscillating, patient, patient as Job, perdurable, perennial, periodic, permanent, perpetual, perseverant, persevering, persistent, persisting, pertinacious, plodding, plugging, preoccupied, pulsating, rapid, rapt, recurrent, regular, relentless, remaining, repeated, repetitive, resolute, reverseless, round-the-clock, running, seamless, sedulous, sempiternal, serried, single-minded, sleepless, slogging, smooth, stable, staccato, staying, steadfast, steady, sticking, straight, strenuous, stubborn, stuttering, sustained, tenacious, timeless, tireless, twenty-four-hour, unabating, unalterable, unalterative, unaltered, unbroken, unceasing, unchangeable, unchanged, unchanging, unconquerable, undaunted, undeflectable, undeviating, undifferentiated, undiscouraged, undrooping, undying, unending, unfailing, unfaltering, unflagging, unflinching, uniform, unintermitted, unintermittent, unintermitting, uninterrupted, unmodifiable, unnodding, unrelaxing, unrelenting, unrelieved, unrestorable, unreturnable, unsleeping, unsparing, unstopped, unsusceptible, unswerving, untiring, unvariable, unvarying, unwavering, unwearied, unwearying, unwinking, utterly attentive, vehement, vibrating, weariless, without end, zealous