The Collaborative International Dictionary of English v.0.48:
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. Inadvertence