The antonyms for "most undiscerning" are "most discerning," "most perceptive," and "most astute." These words refer to people who have a keen sense of judgment and can make astute observations about the world around them. They are able to analyze situations and solve problems efficiently, which sets them apart from the most undiscerning individuals who lack these qualities. People who possess these characteristics are generally highly respected and sought after as advisors in various fields. It is essential to recognize the difference between the two types of individuals when making important decisions, as it can directly impact the outcomes.