When we say someone is conversant in a particular skill or knowledge, it means that they have a good understanding of it. However, if we have to look for antonyms of the phrase "are conversant in," we may use words like unfamiliar with, ignorant of, inexperienced, unskilled, or unacquainted with, which indicate a lack of knowledge or skill in a particular area. These antonyms are opposite to the idea of being conversant, and they suggest a person's lack of familiarity or understanding. It is essential to use the right antonym in the right context to get the right meaning across.