Zealot

1. n. One who is zealous; one who engages warmly in any cause, and pursues his object with earnestness and ardor; especially, one who is overzealous, or carried away by his zeal; one absorbed in devotion to anything; an enthusiast; a fanatical partisan.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.