Source : Webster's Revised Unabridged Dictionary (1913)

Inadmissible \In`ad*mis"si*ble\, a. [Pref. in- not + admissible:
   cf. F. inadmissible.]
   Not admissible; not proper to be admitted, allowed, or
   received; as, inadmissible testimony; an inadmissible
   proposition, or explanation. -- {In`ad*mis"si*bly}, adv.

Source : WordNet®

inadmissible
     adj : not deserving to be admitted; "inadmissible evidence" [ant:
           {admissible}]