Which term describes a brisk and eager action?

The term that describes a brisk and eager action is "alacrity." This word conveys a sense of readiness and enthusiasm to engage in an activity or task. When someone exhibits alacrity, they approach their duties with energy and a willing spirit, reflecting a positive and eager attitude.

The other terms do not align with the idea of briskness or eagerness. "Appall" suggests a reaction of shock or dismay rather than eagerness. "Dissonant" refers to a lack of harmony or agreement, often in music or ideas, which does not relate to action at all. "Bellicose" is used to describe an aggressive or warlike demeanor, indicating a tendency towards fighting rather than a cheerful or eager disposition. Therefore, "alacrity" is the suitable choice that encapsulates the essence of swift and eager action.