deˈcayless,a.rare. [f. decay n. + -less.] Not subject to decay, undecaying. 1828Moir Castle of TimeWks. 1852 II. 399 For shadows..Left not a trace on that decayless sky.1864Neale Seaton. Poems 155 Untended, decayless, Sleeping the infinite sleep, the monarch reposed.