unimpeachable

comparative more unimpeachable · superlative most unimpeachable

1. Not able to be impeached or reproached.

   a gentleman of unimpeachable integrity

   1 more example

   “Patriotism” makes for a slogan that is so unimpeachable it’s arguably even manipulative; as a matter of strategy, it’s harder for opponents to vote against the USA PATRIOT Act than, say, the Enhanced Security Act.

   2022 November 12, Matteo Wong, “How Did America End Up With the Z.O.M.B.I.E. Act?”, in The Atlantic

2. Blameless.
3. Beyond doubt.

   an unimpeachable alibi

   2 more examples

   On the previous day, the prisoner had purchased strychnine at the village chemist’s shop, wearing a disguise by means of which he hoped to throw the onus of the crime upon another man—to wit, Mrs. Inglethorp’s husband, of whom he had been bitterly jealous. Luckily for Mr. Inglethorp, he had been able to produce an unimpeachable alibi.

   1920, Agatha Christie, The Mysterious Affair at Styles, London: Pan Books, published 1954, page 153

   (in Farsi) Today I have proof from an unimpeachable source you are a traitor.

   2017, “Imminent Risk” (28:50 from the start), in Homeland, season 6, episode 7, spoken by Naser (Anthony Azizi)