Impugn:
to cause people to doubt someone’s character, qualities, or reputation by criticizing them:
Are you impugning my competence as a professional designer? [Cambridge Dictionary]
Noted in “Trump has never been in so much peril. Nor has the GOP.” Jennifer Rubin, WaPo:
Trump’s lame overtures to Attorney General Merrick Garland to “reduce the heat” of the political fallout from the Mar-a-Lago search — while simultaneously insinuating that violence might occur if the Justice Department keeps pursuing him — is as disingenuous as it is utterly irrelevant to Garland. The Justice Department’s prosecutors and investigators certainly don’t care if Republicans are still enthralled with Trump. They will go after anyone who engages in acts of violence, as Garland made clear in his remarks last week in which he demanded that people stop impugning and threatening the FBI.
Kinda odd I’ve made it this far through life without actually ever having checked into the meaning of impugn.