Source : Webster's Revised Unabridged Dictionary (1913)

Imperishable \Im*per"ish*a*ble\, a. [Pref. im- not + perishable:
   cf. F. imp['e]rissable.]
   Not perishable; not subject to decay; indestructible;
   enduring permanently; as, an imperishable monument;
   imperishable renown. -- {Im*per"ish*a*ble*ness}, n. --
   {Im*per"ish*a*bly}, adv.

Source : WordNet®

imperishable
     adj 1: not perishable [ant: {perishable}]
     2: unceasing; "an abiding belief"; "imperishable truths" [syn:
        {abiding}, {enduring}]