immarcescible

from The Collaborative International Dictionary of English v.0.48

Immarcescible \Im`mar*ces"ci*ble\, a. [L. immarcescibilis; pref.
   im- not + marcescere to fade: cf. F. immarcescible.]
   Unfading; lasting. [Obs.] --Bp. Hall.
   [1913 Webster]