The Collaborative International Dictionary
Immarcescible
Immarcescible \Im`mar*ces"ci*ble\, a. [L. immarcescibilis; pref.
im- not + marcescere to fade: cf. F. immarcescible.]
Unfading; lasting. [Obs.]
--Bp. Hall.
Wiktionary
immarcescible
a. (context rare English) permanent, enduring; that does not perish.