"Most zestful" refers to a person or thing full of energy, enthusiasm, and excitement. Antonyms for this word may include "lethargic," "lackluster," "apathetic," "unenthusiastic," "uninspiring," and "listless." These words describe a lack of energy, interest, and motivation. If someone or something lacks zest, it means they are dull, lifeless, and unexciting. They may appear lazy, bored, or disinterested. It's important to note that the opposite of "most zestful" may not always be negative. Sometimes, it's okay to take things slow, be calm, and relax without any excitement. It's all about finding the right balance.