The antonyms for the word "most unprolific" are plenty, abundant, fruitful, productive, prolific, and flourishing. These words refer to the degree of productivity and the ability to produce results. If we say that someone or something is abundant, it implies that they are capable of producing a large amount of something. Similarly, if we say that something is prolific, it means that it produces results in large numbers. In contrast, the word unprolific implies a lack of productivity or poor results. Thus, when searching for antonyms for most unprolific, we seek words that describe a state of abundance, productivity, and flourishing.