Source : Webster's Revised Unabridged Dictionary (1913)

Immobile \Im*mo"bile\, a. [L. immobilis: cf. F. immobile. See
   {Immobility}.]
   Incapable of being moved; immovable; fixed; stable. --Prof.
   Shedd.

Source : WordNet®

immobile
     adj 1: not capable of movement or of being moved [ant: {mobile}]
     2: securely fixed in place; "the post was still firm after
        being hit by the car" [syn: {fast}, {firm}]