contradict (v.) Look up contradict at Dictionary.com
1570s, "speak against," also "assert the contrary" (1580s), from Latin contradictus, past participle of contradicere, in classical Latin contra dicere "to speak against," from contra "against" (see contra) + dicere "to say, speak" (from PIE root *deik- "to show," also "pronounce solemnly"). Related: Contradicted; contradicting; contradictive.