Not perishable.

Roget 112: perpetual, eternal; everduring^†, everlasting, ever-living, ever-flowing; continual, sempiternal^†; coeternal; endless, unending; ceaseless, incessant, uninterrupted, indesinent^†, unceasing; endless, unending, interminable, having no end; unfading^†, evergreen, amaranthine; neverending^†, never-dying, never-fading; deathless, immortal, undying, imperishable.    ... show more

Roget 150: unchangeable, immutable; unaltered, unalterable; not to be changed, constant; permanent etc. 141; invariable, undeviating; stable, durable; perennial etc. (diuturnal) 110^†.    fixed, steadfast, firm, fast, steady, balanced; confirmed, valid; fiducial^†; immovable, irremovable, riveted, rooted; settled, established etc. v.; vested; incontrovertible, stereotyped, indeclinable.    tethered, anchored, moored, at anchor, on a rock, rock solid, firm as a rock; firmly seated, firmly established etc. v.; deep-rooted, ineradicable; inveterate; obstinate etc. 606.    transfixed, stuck fast, aground, high and dry, stranded.    [movable object rendered unmovable] stuck, jammed; unremovable; quiescent etc. 265; deterioration etc. 659.    indefeasible, irretrievable, intransmutable^†, incommutable^†, irresoluble^†, irrevocable, irreversible, reverseless^†, inextinguishable, irreducible; indissoluble, indissolvable^†; indestructible, undying, imperishable, incorruptible, indelible, indeciduous^†; insusceptible, insusceptible of change.    ... show more

Roget 873: distinguished, distingue [Fr.], noted; of note etc. n.; honored etc. v.; popular; fashionable etc. 852.    in good odor in; favor, in high favor; reputable, respectable, creditable.    remarkable etc. (important) 642; notable, notorious; celebrated, renowned, ion every one's mouth, talked of; famous, famed; far-famed; conspicuous, to the front; foremost; in the front rank, in the ascendant.    imperishable, deathless, immortal, never fading, aere perennius [Lat.]; time honored.    illustrious, glorious, splendid, brilliant, radiant; bright etc. 420; full-blown; honorific.    eminent, prominent; high etc. 206; in the zenith; at the head of, at the top of the tree; peerless, of the first water.   ; superior etc. 33; supereminent, preeminent.    great, dignified, proud, noble, honorable, worshipful, lordly, grand, stately, august, princely.    imposing, solemn, transcendent, majestic, sacred, sublime, heaven-born, heroic, sans peur et sans reproche [Fr.]; sacrosanct.    ... show more

Lasting a long time:
— Imperishable truths.

synonyms: abiding, enduring.