"Am prolific" means that someone is productive or creative in their work. There are many antonyms for this phrase, such as "unproductive," "uninspired," "uncreative," "unsatisfying," "unfruitful," "unsuccessful," "unaccomplished," "unproductive," "unsuccessful," "ineffective," "inefficient," "inept," "incapable," "incompetent," and "fruitless". These words describe someone who is not achieving their full potential, either because they lack creativity or motivation, or because they simply cannot produce the desired results. While being prolific can be a great asset in any profession, it's important to remember that it's not the only measure of success, and that there are many ways to contribute to a productive and fulfilling career.