The Collaborative International Dictionary of English v.0.48:

Disfranchise \Dis*fran"chise\, v. t. [imp. & p. p.
   Disfranchised; p. pr. & vb. n. Disfranchising.] [Cf.
   Diffranchise.]
   To deprive of a franchise or chartered right; to dispossess
   of the rights of a citizen, or of a particular privilege, as
   of voting, holding office, etc.
   [1913 Webster]

         Sir William Fitzwilliam was disfranchised. --Fabyan
                                                  (1509).
   [1913 Webster]

         He was partially disfranchised so as to be made
         incapable of taking part in public affairs.
                                                  --Thirlwall.
   [1913 Webster]

WordNet (r) 3.0 (2006):

disfranchise
    v 1: deprive of voting rights [syn: disenfranchise,
         disfranchise] [ant: enfranchise]