The phrase "most well-versed" means to be highly knowledgeable in a particular field or subject. Its antonyms are phrases that describe a lack of knowledge or expertise, such as "ignorant," "amateur," or "novice." Other antonyms can include "unfamiliar," "inexperienced," or "ill-informed." Those who are not well-versed are often described as being unskilled, uninformed, or inadequate, highlighting the importance of having a deep understanding of a subject or field. It's essential to remember that everyone starts as a novice and can work towards becoming well-versed with dedication and practice.