Antonyms: Antonym of “prolific” is:

The word "prolific" means producing much fruit or foliage or many offspring; or producing many works, results, or items. It conveys a sense of high productivity, abundance, and fertility. To find its antonym, we need a word that means the opposite of producing much or being fertile. "Barren" is the correct antonym, meaning (of land) too poor to produce much or any vegetation, or (of a female animal) unable to produce offspring.

• "Productive" is incorrect as it is a synonym, meaning capable of producing.
• "Abundant" is also a synonym, meaning existing in large quantities.
• "Fertile" is another synonym, directly meaning capable of producing vegetation or offspring.