overenthusiasm

noun

1. absorbing or controlling possession of the mind by any interest or pursuit; lively interest: He shows marked enthusiasm for his studies.
2. an occupation, activity, or pursuit in which such interest is shown: Hunting is his latest enthusiasm.
3. any of various forms of extreme religious devotion, usually associated with intense emotionalism and a break with orthodoxy.

noun

1. ardent and lively interest or eagerness
2. an object of keen interest; passion
3. archaic extravagant or unbalanced religious fervour
4. obsolete possession or inspiration by a god

n.c.1600, from Middle French enthousiasme (16c.) and directly from Late Latin enthusiasmus, from Greek enthousiasmos “divine inspiration,” from enthousiazein “be inspired or possessed by a god, be rapt, be in ecstasy,” from entheos “divinely inspired, possessed by a god,” from en “in” (see en- (2)) + theos “god” (see Thea). Acquired a derogatory sense of “excessive religious emotion” (1650s) under the Puritans; generalized sense of “fervor, zeal” (the main modern sense) is first recorded 1716.