Source : Webster's Revised Unabridged Dictionary (1913)

Zealot \Zeal"ot\, n. [F. z['e]lote, L. zelotes, Gr. ?. See
   {Zeal}.]
   One who is zealous; one who engages warmly in any cause, and
   pursues his object with earnestness and ardor; especially,
   one who is overzealous, or carried away by his zeal; one
   absorbed in devotion to anything; an enthusiast; a fanatical
   partisan.

         Zealots for the one [tradition] were in hostile array
         against zealots for the other.           --Sir J.
                                                  Stephen.

         In Ayrshire, Clydesdale, Nithisdale, Annandale, every
         parish was visited by these turbulent zealots.
                                                  --Macaulay.

Source : WordNet®

Zealot
     n 1: a member of an ancient Jewish sect in Judea in the first
          century who fought to the death against the Romans and
          who killed or persecuted Jews who collaborated with the
          Romans
     2: a fervent and even militant proponent of something [syn: {partisan},
         {drumbeater}]