"Most equipollent" means the most equivalent or closely matched. Antonyms for the word "most equipollent" include: unequal, unbalanced, dissimilar, opposite, different, variant, divergent, mismatched, and inconsistent. These antonyms signify a lack of similarity or harmony between two or more things. Unequal and unbalanced imply unequal distribution, whether in size, strength, or value. Dissimilar and opposite suggest fundamental differences or contrasting qualities. Variant, divergent, and mismatched denote varying degrees of incompatibility or inconsistency. So, if you want to express the idea of difference or a lack of match, you can use any of these antonyms in place of "most equipollent".