The Collaborative International Dictionary of English v.0.48:

Moralist \Mor"al*ist\, n. [Cf. F. moraliste.]
   1. One who moralizes; one who teaches or animadverts upon the
      duties of life; a writer of essays intended to correct
      vice and inculcate moral duties. --Addison.
      [1913 Webster]

   2. One who practices moral duties; a person who lives in
      conformity with moral rules; one of correct deportment and
      dealings with his fellow-creatures; -- sometimes used in
      contradistinction to one whose life is controlled by
      religious motives.
      [1913 Webster]

            The love (in the moralist of virtue, but in the
            Christian) of God himself.            --Hammond.
      [1913 Webster]

WordNet (r) 3.0 (2006):

moralist
    n 1: a philosopher who specializes in morals and moral problems
    2: someone who demands exact conformity to rules and forms [syn:
       martinet, disciplinarian, moralist]