The word "active" serves as the antonym for "nonactive." Therefore, some words that can be considered as antonyms for "most nonactive" include active, dynamic, energetic, lively, and busy. Active is the closest antonym, suggesting an opposite meaning of vigorous, physically or mentally engaged, or productive. Dynamic carries a sense of forcefulness or a continuously changing nature. Energetic implies an abundance of physical or mental energy, enthusiasm, or a willingness to act. Lively refers to being animated, spirited, or effervescent. Busy suggests being fully engaged in a constant or relentless activity. Each of these words describes a person or thing with a different type of non-zero activity, in opposition to the inactivity implied by the term "nonactive.