Being on par with someone or something means being equal in rank, status, or quality. Opposite words for this phrase could include "inferior," "unequal," "inferiority," and "disparity." "Inferior" indicates that something or someone is beneath in rank or quality. Similarly, "unequal" emphasizes the disparities or differences in two things or anything. The word "inferiority" denotes the condition of being lower in rank, status, quality than someone or something else. Lastly, "disparity" emphasizes the difference in qualities, quantities, or ranks of two things. These antonyms can be handy while constructing sentences or comparing two things.