"Most comer," meaning someone who is likely to succeed, has various antonyms depending on the context. In the academic field, words like "underachiever," "poor-performer," or "mediocre student" could be antonyms to "most comer." In the business world, words such as "underdog," "non-achiever," or "loser" could be antonyms. However, it is essential to note that each context might have different antonyms for the term "most comer." For instance, in the sporting world, a "least comer" can be used as an antonym to "most comer." It is crucial to choose the antonym of the "most comer" based on the context, to present the intended message accurately.