W: (adj) contradictory [Related to: contradict] (in disagreement) "the figures are at odds with our findings"; "contradictory attributes of unjust justice and loving vindictiveness"- John Morley
W: (adj) contradictory [Related to: contradict] (of words or propositions so related that both cannot be true and both cannot be false) "`perfect' and `imperfect' are contradictory terms"
W: (n) negation [Related to: negate] ((logic) a proposition that is true if and only if another proposition is false)
S: (v) neutralize, neutralise, nullify, negate (make ineffective by counterbalancing the effect of) "Her optimism neutralizes his gloom"; "This action will negate the effect of my efforts"