(n.) The placing of a before another, which, by ordinary rules, ought to follow it.

antagonism anteposition antipathy antipode antipodes antipole antonym clashing collision con conflict confrontation confrontment contention contra contradiction contradictory contradistinction contraindication contraposition contrariety contrary contrast converse counter counterbalance countercheck counterpoint counterpoise counterpole counterposition counterterm cross-purposes disagreement discrepancy foil hostility inconsistency inimicalness inverse obverse offset opposing opposite opposite number oppositeness opposition opposure oppugnance oppugnancy perversity polar opposition polarity polarization posing against repugnance reverse setoff showdown the contrary the other side vis-a-vis