- above suspicion; impossible to discredit; impeccable: unimpeachable motives.
Origin of unimpeachable
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for unimpeachably
Steve Lesher brought in an unimpeachably sourced account of the Supreme Court's deliberations in the Nixon tape case.Newsweek’s Watergate Legacy
December 29, 2012
So it must be a welcome change for Curry to come back into the public fold in such a unimpeachably positive way.Ann Curry’s Twitter Rehab
December 23, 2012
Not folly in believing in him and his authority—on that he was unimpeachably sincere.Mrs. Maxon Protests
It is her ambition to lead, but to lead nobly and unimpeachably.Search-Light Letters
We strive to hope that, though almost as curious, it is not so unimpeachably appropriate as the one quoted above.Mathieu Ropars: et cetera
Yet Miss Quisanté laughed, as a man's relatives often will although the rest of the world is unimpeachably grave.Quisant
The authorities on which Mrs. Oliphant relies for her facts are unimpeachably good.
- unquestionable as to honesty, truth, etc
Word Origin and History for unimpeachably
Online Etymology Dictionary, © 2010 Douglas Harper