1. (a.) Inconsistent; opposed to what has been already been asserted\; also, mutually contradicting.

2. (a.) Opposing or opposed; repugnant.

3. (n.) A proposition or thing which denies or opposes another; contrariety.

4. (n.) propositions with the same terms, but opposed to each other both in quality and quantity.

abjuratory abnegative absonant adversary adversative adverse adversive alien ambiguous ambivalent antagonistic anti antipathetic antipodal antipode antipodean antipole antithesis antithetic antithetical antonymous at cross-purposes at loggerheads at odds at variance at war balancing breakaway clashing compensating competitive con conflicting confounding confronting confutative confuting contra contradicting contradistinct contrapositive contrarious contrary contrary to reason contrasted converse counter counteractant counteracting counteractive counterbalancing counterpoised counterpole countervailing counterworking cranky cross crotchety dead against denying differing disaccordant disaffirming disagreeable disagreeing disallowing disavowing disclaiming discordant discrepant disharmonious disowning disproportionate dissentient dissident dissonant divergent enemy eyeball to eyeball fallacious faulty flawed fractious grating hostile illogical immiscible inaccordant inauthentic incompatible inconclusive incongruous inconsequent inconsequential inconsistent inharmonious inimical invalid inverse irrational jangling jarring loose negating negative negatory nonconformist noncooperative nonscientific not following nullifying obstinate obverse opponent opposed opposing opposite oppositional oppositive oppugnant out of accord out of whack overthwart paradoxical paralogical perverse polar reactionary reasonless recalcitrant recanting refractory refutative refutatory refuting renitent renunciative renunciatory repudiative repugnant resistant reverse revocative revocatory revolutionary rival self-annulling self-contradictory self-refuting senseless squared off unauthentic uncongenial unconnected uncooperative unfavorable unfriendly unharmonious unphilosophical unpropitious unreasonable unscientific variant without reason