These nouns denote powerful, intense emotion. Passion is a deep, overwhelming emotion: “There is not a passion so strongly rooted in the human heart as envy” (Richard Brinsley Sheridan). The term may signify sexual desire or anger: “He flew into a violent passion and abused me mercilessly” (H.G. Wells). Fervor is great warmth and intensity of feeling: “The union of the mathematician with the poet, fervor with measure, passion with correctness, this surely is the ideal” (William James). Fire is burning passion: “In our youth our hearts were touched with fire” (Oliver Wendell Holmes, Jr.) Zeal is strong, enthusiastic devotion to a cause, ideal, or goal and tireless diligence in its furtherance: “Laurie [resolved], with a glow of philanthropic zeal, to found and endow an institution for … women with artistic tendencies” (Louisa May Alcott). Ardor is fiery intensity of feeling: “the furious ardor of my zeal repressed” (Charles Churchill).