Enthusiastic

google

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late 16th century (denoting a person believing that he or she is divinely inspired ): from Greek enthousiastikos, from enthous ‘possessed by a god’ (see enthusiasm).

wiktionary

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Ancient Greek ἐνθουσιαστικός(enthousiastikós), from ἐνθουσιασμός(enthousiasmós) or ἐνθουσιάζω(enthousiázō) + -τικός(-tikós)

etymonline

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enthusiastic (adj.)

c. 1600, "pertaining to possession by a deity," from Greek enthousiastikos "inspired," from enthousiazein "be possessed or inspired by a god" (see enthusiasm). Meaning "pertaining to irrational delusion in religion" is from 1690s. The main modern sense, in reference to feelings or persons, "intensely eager, rapturous," is from 1786. Related: Enthusiastically.