abiding, adamantine, age-long, aged, alive, ancient, antique, assiduous, bulky, cartilaginous, changeless, chewy, chronic, chronological, cohesive, constant, continual, continuing, continuous, coriaceous, dense, diligent, diuturnal, dogged, drawn-out, durable, durational, durative, eidetic, endless, enduring, eternal, evergreen, everlasting, extended, faithful, fibrous, firm, fixed, fresh, frozen, green, gristly, hard, hardy, heavy, immobile, immutable, inalterable, incessant, incommutable, inconvertible, indefatigable, indefeasible, indelible, indissoluble, indomitable, industrious, inert, insistent, insusceptible of change, intact, interminable, intransient, intransmutable, invariable, inveterate, invincible, inviolate, irretrievable, irreversible, irrevocable, kept in remembrance, languishing, leatherlike, leathery, lengthened, lingering, long-continuing, long-drawn-out, long-drawn, long-lasting, long-lived, long-pending, long-standing, long-term, long-winded, long, longeval, longevous, loyal, macrobiotic, marathon, massive, never-tiring, noble, nonreturnable, nonreversible, obstinate, of long duration, of long standing, old, overlong, patient, patient as Job, perdurable, perduring, perennial, permanent, perpetual, perseverant, persevering, persistent, persisting, pertinacious, plodding, plugging, preoccupied, prolonged, protracted, quiescent, rapt, recalled, recollected, relentless, remaining, remembered, resistant, resolute, retained, reverseless, rigid, ropy, rugged, sedulous, sempervirent, sempiternal, sinewy, single-minded, sleepless, slogging, solid, sound, spun-out, stable, static, stationary, staying, steadfast, steady, stiff, stout, stretched-out, stringy, strong, stubborn, sturdy, sustained, temporal, tenacious, tireless, torpid, tough, tough as leather, unabating, unalterable, unalterative, unaltered, unceasing, unchangeable, unchanged, unchanging, unchecked, unconquerable, undaunted, undeflectable, undestroyed, undeviating, undiscouraged, undrooping, undying, unfading, unfailing, unfaltering, unflagging, unflinching, unforgotten, unintermitting, uninterrupted, unmodifiable, unnodding, unrelaxing, unrelenting, unremitting, unrestorable, unreturnable, unshifting, unsleeping, unsusceptible, unswerving, untiring, unvariable, unvaried, unvarying, unwavering, unwearied, unwearying, unwinking, unyielding, utterly attentive, vigorous, viscid, vital, vivid, weariless, well-built, well-constructed, well-founded, well-grounded, well-made, wiry