contradict
Concise Oxford English Dictionary © 2008 Oxford University Press:
contradict/kɒntrəˈdɪkt/
▶verb deny the truth of (a statement) by asserting the opposite.
■ assert the opposite of a statement made by (someone).
– derivatives
contradictor noun.
contradictor noun.
– origin C16: from L. contradict-, contradicere ‘speak against’.
'contradict' also found in these Oxford entries:

