Unequivalence refers to the state of being unequal or not equivalent. Antonyms for this word would include equivalence, equality, similarity, and balance. Equivalence implies that two things are of equal value, importance or significance, and are interchangeable. Equality refers to a state of being equal in status, rights, or opportunities. A synonym for similarity is consistency, which suggests that two things or concepts share common characteristics or traits. Lastly, balance implies that the two things are equal in weight or importance, and have a stabilizing effect on one another. In summary, the antonyms for unequivalence are equivalence, equality, similarity, and balance.