Antonyms for the term "being proficient" might include phrases such as "incompetent," "unskilled," or "novice." These words suggest a lack of ability or experience in a particular task or subject, and indicate that the individual is not yet capable of performing at a high level. Other antonyms could include terms such as "clumsy," "inept," or "awkward," which imply a certain level of clumsiness or lack of coordination in one's actions. Whatever the specific antonym used, the opposite of being proficient is a state of inexperience or incapacity, which requires further training or education to overcome.