enthusiasmus

Enthusiasm is a feeling of intense interest, eagerness, and active participation in a person, activity, or cause. It is often described as a positive affect that motivates engagement beyond ordinary interest and can be contagious in social and collaborative settings. The word in English comes from the Greek enthousiasmos, meaning "being possessed by a god" (en "in", theos "god"), and was later secularized to denote ardor and zeal. In German, the cognate term Enthusiasmus is used with a similar meaning; in many other languages the word is borrowed as well.

Historically, enthusiasm referred to divine inspiration or prophetic excitation in ancient and religious contexts. In modern usage it denotes a strong positive attitude toward an object or activity without necessarily implying irrationality. Psychology treats enthusiasm as a motivational state that supports persistence, effort, and learning, while also noting that excessive zeal can lead to overconfidence, dogmatism, or neglect of counterevidence.

In social and organizational contexts, enthusiasm is often seen as contagious and beneficial for morale and cooperation, though it may also create pressure to display enthusiasm publicly. Measuring enthusiasm is typically informal, inferred from behavior, persistence, and verbal expression rather than from a fixed scale.

Related concepts include zeal, ardor, fervor, passion, and motivation.