Source : Webster's Revised Unabridged Dictionary (1913)

Extensile \Ex*ten"sile\a.
   Suited for, or capable of, extension; extensible. --Owen.

Source : WordNet®

extensile
     adj : capable of being protruded or stretched or opened out; "an
           extensile tongue"; "an extensible measuring rule" [syn:
            {extensible}] [ant: {nonextensile}]