1. One who is sent on a mission, especially one sent to do religious or charitable work in a territory or foreign country.
2. One who attempts to persuade or convert others to a particular program, doctrine, or set of principles; a propagandist.

1. Of or relating to missions or missionaries.
2. Engaged in the activities of a mission or missionary.
3. Tending to propagandize or use insistent persuasion: missionary fervor.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.