Which word describes someone who is zestfully enthusiastic and bubbling with energy?

The word that best describes someone who is zestfully enthusiastic and bubbling with energy is "ebullient." This term specifically captures a sense of overflowing enthusiasm and vitality, often accompanied by cheerful expressions or vibrant behavior. An ebullient person tends to radiate joy and energy, engaging those around them with their lively and animated presence.

While "eager," "exuberant," and "ardent" also convey enthusiasm, they do not encompass the same level of lively energy. "Eager" generally suggests a keen desire or willingness but doesn’t necessarily imply an outward expression of that energy. "Exuberant" is similar and can denote high spirits and enthusiasm; however, it does not quite capture the bubbling, effervescent quality that "ebullient" conveys. "Ardent" emphasizes passionate intensity but lacks the inherently joyful, overflowing energy implied by "ebullient." Therefore, "ebullient" is the most accurate choice for describing someone with that zestful enthusiasm and vibrant energy.