(a.) Pertaining to antithesis, or opposition of words and sentiments; containing, or of the nature of, antithesis; contrasted.

adversary adversative adverse adversive alien antagonistic anti antipathetic antipodal antipodean antithetic antonymous at cross-purposes balancing clashing compensating competitive con conflicting confronting contradictory contradistinct contrapositive contrarious contrary contrasted converse counter counterbalancing counterpoised countervailing cross dead against disaccordant discordant discrepant dissentient enemy eyeball to eyeball eyeball-to-eyeball facing fractious hostile inconsistent inimical inverse negative noncooperative obstinate obverse opponent opposed opposing opposite oppositional oppositive oppugnant overthwart perverse polar polaric polarized recalcitrant refractory repugnant reverse rival squared off uncooperative unfavorable unfriendly unpropitious