Source : Webster's Revised Unabridged Dictionary (1913)

Dissident \Dis"si*dent\, a. [L. dissidens, -entis, p. pr. of
   dissidere to sit apart, to disagree; dis- + sedere to sit:
   cf. F. dissident. See {Sit}.]
   No agreeing; dissenting; discordant; different.

         Our life and manners be dissident from theirs.
                                                  --Robynson
                                                  (More's
                                                  Utopia).

Dissident \Dis"si*dent\, n. (Eccl.)
   One who disagrees or dissents; one who separates from the
   established religion.

         The dissident, habituated and taught to think of his
         dissidenc? as a laudable and necessary opposition to
         ecclesiastical usurpation.               --I. Taylor.

Source : WordNet®

dissident
     adj 1: characterized by departure from accepted beliefs or
            standards [syn: {heretical}, {heterodox}]
     2: disagreeing, especially with a majority [syn: {dissentient},
         {dissenting(a)}]

dissident
     n : a person who dissents from some established policy [syn: {dissenter},
          {protester}, {objector}, {contestant}]