enthusiasm (n.) Look up enthusiasm at Dictionary.com
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 theo-). 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.