(transitive, obsolete) To assault, attack. / (transitive) To verbally assault, especially to argue against an opinion, motive, or action; to question the truth or validity of.

That can be impugned; open to (verbal) attack, open to question.

plural of impugnation

present participle of impugn

The act of impugning / (law) The act of appealing or revoking

One who impugns; one who opposes or contradicts.

simple past tense and past participle of impugn

plural of impugner

Third-person singular simple present indicative form of impugn

The act of impugning, or the state of being impugned.