Impugn

глагол [литературно-книжное] оспаривать, опровергать; ставить под сомнение, подвергать сомнению Синоним(ы): contest, dispute, question, challenge

Большой англо-русский словарь

Impugn

transitive verb Etymology: Middle English, from Anglo-French empugner, from Latin inpugnare, from in- + pugnare to fight — more at pungent 1. to assail by words or arguments; oppose or attack as false or lacking integrity Example: impugned the defendant's character 2. obsolete a. assail b. resistimpugnable adjectiveimpugner noun

Merriam-Webster's Collegiate Dictionary