Contraposition

n.	1.	A placing over against; opposite position.
	2.	(Logic) A so-called immediate inference which consists in denying the original subject of the contradictory predicate; e. g.: Every S is P; therefore, no Not-P is S.

antagonism, antipathy, antithesis, backlash, bucking, challenge, clashing, collision, con, conflict, confrontation, confutation, contention, contradiction, contradistinction, contraindication, contrariety, contrast, contravention, contraversion, counteraction, counterposition, counterworking, crankiness, cross-purposes, crosscurrent, crossing, crotchetiness, denial, disagreement, discrepancy, dissent, friction, head wind, hostility, impugnation, impugnment, inconsistency, inimicalness, interference, kick, negation, nonconformity, opposing, oppositeness, opposition, opposure, oppugnance, oppugnancy, oppugnation, perverseness, perversity, polarity, reaction, rebutment, rebuttal, recalcitrance, recoil, refusal, rejection, renitency, repercussion, repugnance, resistance, revolt, showdown, standing against, swimming upstream, traversal, undercurrent