The Collaborative International Dictionary of English v.0.48:

Propagandist \Prop`a*gan"dist\, n. [Cf. F. propagandiste.]
   A person who devotes himself to the spread of any system of
   principles. "Political propagandists." --Walsh.
   [1913 Webster]
   [1913 Webster]

WordNet (r) 3.0 (2006):

propagandist
    adj 1: of or relating to or characterized by propaganda [syn:
           propagandist, propagandistic]
    n 1: a person who disseminates messages calculated to assist
         some cause or some government