disenable

from WordNet (r) 3.0 (2006)

disenable
    v 1: make unable to perform a certain action; "disable this
         command on your computer" [syn: {disable}, {disenable},
         {incapacitate}] [ant: {enable}]

from The Collaborative International Dictionary of English v.0.48

Disenable \Dis`en*a"ble\, v. t. [Pref. dis- + enable.]
   To disable; to disqualify.
   [1913 Webster]

         The sight of it might damp me and disenable me to
         speak.                                   --State Trials
                                                  (1640).
   [1913 Webster]