From Longman Dictionary of Contemporary Englishimpugnim‧pugn /ɪmˈpjuːn/ verb [transitive] formal CRITICIZEto express doubts about someone’s honesty, courage, ability etc I did not mean to impugn her professional abilities.→ See Verb table
Examples from the Corpus
impugn• Andrew's own orthodoxy was never impugned.• The irony is that in other Arab countries it is the opposition that impugns democracy as the constitutional foundation of the republic.• This is a knowledge which has been impugned in literature, and which has deteriorated there.• Pollutions which attract substantial publicity risk impugning the agency's competence.• Gerlick has filed a complaint impugning the judge's integrity.• In a press conference, Bush supporters used the strongest language so far to impugn the legitimacy of the continued Florida recounts.• Without impugning the motives of any believer in this, I point out that it reeks of a vile and dangerous racism.• Key field support teams were said to be overtly impugning the reputations of colleagues within earshot of customers.• Political combatants now routinely impugn the very moral fiber of their opponents.Origin impugn (1300-1400) Latin impugnare, from pugnare “to fight” 