Source : Webster's Revised Unabridged Dictionary (1913)

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.

   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.

Source : WordNet®

neologist
     n : a lexicographer of new words and expressions