1 (often foll. by for, about) a strong interest or admiration. b great eagerness.
2 an object of enthusiasm.
3 archaic extravagant religious emotion.
Etymology: F enthousiasme or LL enthusiasmus f. Gk enthousiasmos f. entheos possessed by a god, inspired (as EN-(2), theos god)
Useful english dictionary. 2012.