'enthusiastic' originates from Greek, specifically the word 'enthousiasmos,' where 'en-' meant 'in' and 'theos' meant 'god.'

'enthousiasmos' transformed into the Latin word 'enthusiasmus,' and eventually became the modern English word 'enthusiastic' through Middle English.

Initially, it meant 'possessed by a god,' but over time it evolved into its current meaning of 'showing intense enjoyment or interest.'