Zeal :: Zeal (n.) Passionate ardor in the pursuit of anything; eagerness in favor of a person or cause; ardent and active interest; engagedness; enthusiasm; fervor.
Zealot :: Zealot (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..
Zealotical :: Zealotical (a.) Like, or suitable to, a zealot; ardently zealous..
Zealotism :: Zealotism (n.) The character or conduct of a zealot; zealotry.