The Collaborative International Dictionary of English v.0.48:

Preterist \Pret"er*ist\, n. [Pref. preter- + -ist.]
   1. One whose chief interest is in the past; one who regards
      the past with most pleasure or favor.
      [1913 Webster]

   2. (Theol.) One who believes the prophecies of the Apocalypse
      to have been already fulfilled. --Farrar.
      [1913 Webster]

WordNet (r) 3.0 (2006):

preterist
    n 1: a theologian who believes that the Scripture prophecies of
         the Apocalypse (the Book of Revelation) have already been
         fulfilled