The Collaborative International Dictionary of English v.0.48:

Neologist \Ne*ol"o*gist\, n. [Cf. F. n['e]ologiste.]
   1. One who introduces new words or new senses of old words
      into a language.

   Syn: verbarian.
        [1913 Webster]

   2. An innovator in any doctrine or system of belief,
      especially in theology; one who introduces or holds
      doctrines subversive of supernatural or revealed religion;
      a rationalist, so-called.
      [1913 Webster] Neologistic

WordNet (r) 3.0 (2006):

neologist
    n 1: a lexicographer of new words and expressions