Intense enjoyment, interest or approval towards something
In modern usage, enthusiasm refers to intense enjoyment, interest, or approval expressed by a person. The term is related to playfulness, inventiveness, optimism, zest, verve, and high energy. The word was originally used to refer to a person possessed by God, or someone who exhibited intense piety. Historical usage. The word enthusiasm originates from the Greek ἐνθουσιασμός from ἐν (en, “in”) and θεός (theós, “god”), meaning "inspired or possessed by [a] god".
https://en.wikipedia.org/wiki/Enthusiasm