The Collaborative International Dictionary of English v.0.48:

Suffragist \Suf"fra*gist\, n.
   1. One who possesses or exercises the political right of
      suffrage; a voter.
      [1913 Webster]

   2. One who has certain opinions or desires about the
      political right of suffrage; as, a woman suffragist.
      [1913 Webster]

            It is curious that . . . Louisa Castelefort should
            be obliged after her marriage immediately to open
            her doors and turn ultra liberal, or an universal
            suffragist.                           --Miss
                                                  Edgeworth.
      [1913 Webster]

WordNet (r) 3.0 (2006):

suffragist
    n 1: an advocate of the extension of voting rights (especially
         to women)