Source : Webster's Revised Unabridged Dictionary (1913)

Immiscible \Im*mis"ci*ble\, a. [Pref. im- not + miscible: cf. F.
   immiscible.]
   Not capable of being mixed or mingled.

         A chaos of immiscible and conflicting particles.
                                                  --Cudworth.

Source : WordNet®

immiscible
     adj : (chemistry, physics) incapable of mixing [syn: {unmixable}]
           [ant: {miscible}]