Zeal /(zēl)/

Zeal

n.
  1. Passionate ardor in the pursuit of anything; eagerness in favor of a person or cause; ardent and active interest; engagedness; enthusiasm; fervor.
    I bear them record that they have a zeal of God, but not according to knowledge.
    — Rom. x. 2.
    A zeal for liberty is sometimes an eagerness to subvert with little care what shall be established.
  2. A zealot. [Obs.]

Zeal

v. i.
  1. To be zealous. [Obs. & R.]