The term "more middlemost" is a comparative form of the adjective middlemost, which means the most central, equidistant, or intermediate. Antonyms for "more middlemost" could be extreme, outlier, or marginal. Extreme refers to something that is farthest from the center, while outlier highlights something that is significantly different from the rest. Marginal, on the other hand, suggests the edge or the periphery, implying that it is not at the center. These antonyms are relevant when describing places, objects, or people that are not in the middle or the central part of a particular context or situation.