Wiktionary
a. That does not decay; lasting, imperishable.
Usage examples of "undecaying".
Shokerandit had seen pictures in natural history books of how branches and leaves would dissolve to form a solid resin plug, protecting the featureless and undecaying tree until it released its seed in the following Great Spring.
The victor in this contrived war between himself and March would be trapped forever with an undecaying corpse on the stage set of a magical western, condemned to a limbo in which he would feed on deathly beetles and drink bitter water from a fountain whose splashing kept growing louder and louder.
So shall that name be syllabled anew In all the tongues of all the tribes of men: I that have been through immemorial years Dust in the dust of my forgotten time Shall live in accents shaped of blood-warm breath, Yea, rise in mortal semblance, newly born In shining stone, in undecaying bronze, And stand on high, and look serenely down On the new race that calls the earth its own.