What is the greek word for enthusiasm?

There isn't one single perfect Greek word translation for "enthusiasm." The best choice depends on the nuance you want to convey. However, some possibilities include:

* ἔνθεος (entheos): This word literally means "inspired by a god" or "possessed by a god." It suggests a divine or ecstatic source of passionate energy, which can be close to the feeling of enthusiasm, especially in a religious or artistic context.

* ζῆλος (zêlos): This translates to "zeal," "rivalry," or "emulation." While not a direct synonym for enthusiasm, zeal often involves passionate dedication and fervent energy, similar to enthusiasm.

* A phrase might be needed to capture the full meaning. For example, μεγάλην θέρμην ἔχειν (megalēn thermēn echein), meaning "to have great warmth," could describe the feeling of enthusiasm.

Therefore, depending on the context, entheos or zêlos might be the closest single-word options, but a descriptive phrase might be more accurate.