Douglas Harper's Etymology Dictionary
immarcessible
"unfading, imperishable," 1540s, from Late Latin immarcessabilis from assimilated form of in- "not" (see in- (1)) + marcessare "to wither, pine away."
Usage examples of "immarcessible".
Master somewhiles doat, In dreamings on a docile universe Beneath an immarcessible Charlemagne.
Here flesh, there phantom, livelier after rout: The Seaman piping aye to the rightabout, Distracted Europe's Master, puffed remote Those Indies of the swift Macedonian, Whereon would Europe's Master somewhiles doat, In dreamings on a docile universe Beneath an immarcessible Charlemagne.