Which term refers to someone who is high-spirited and enthusiastic?

The term that refers to someone who is high-spirited and enthusiastic is "exuberant." This word captures the essence of a person who displays lively energy, excitement, and enthusiasm. When someone is exuberant, they are often seen as cheerful, full of vitality, and eager, which aligns perfectly with the concept of being high-spirited.

In contrast, the other terms do not convey enthusiasm or high spirits. "Serene" describes a state of calmness and tranquility, which is quite different from the lively energy of exuberance. Meanwhile, "apathetic" and "indifferent" both indicate a lack of interest, enthusiasm, or concern, which is the opposite of being high-spirited. Thus, "exuberant" is the most fitting choice, as it embodies the qualities of enthusiasm and vivacity.