verb (v)

• be in contradiction with(verb.stative)

  Synonym:
  belie, contradict
  

  source: wordnet30
• deny the truth of(verb.communication)

  Synonym:
  contradict, contravene
  

  source: wordnet30
• prove negative; show to be false(verb.cognition)

  Synonym:
  contradict
  Antonym:
  affirm, confirm, corroborate, substantiate, support, sustain
  

  source: wordnet30
• make ineffective by counterbalancing the effect of(verb.change)

  Example:
  This action will negate the effect of my efforts.
  

  Synonym:
  neutralise, neutralize, nullify
  

  source: wordnet30