impugning

/IH0 M P Y UW1 N IH0 NG/
verb
  1. 1

    To assault, attack.

  2. 2

    To verbally assault, especially to argue against an opinion, motive, or action; to question the truth or validity of.

Source: https://en.wiktionary.org/wiki/impugn, https://en.wiktionary.org/wiki/impugning