Source : Webster's Revised Unabridged Dictionary (1913)

Pursuer \Pur*su"er\, n.
   1. One who pursues or chases; one who follows in haste, with
      a view to overtake.

   2. (Eccl. & Scots Law) A plaintiff; a prosecutor.

Source : WordNet®

pursuer
     n 1: a person who is pursuing and trying to overtake or capture;
          "always before he had been able to outwit his pursuers"
          [syn: {chaser}]
     2: a person who pursues some plan or goal; "a pursuer of truth"