Unimpeachable(a.) Not impeachable; not to be called in question; exempt from liability to accusation; free from stain, guilt, or fault; irreproachable; blameless; as, an unimpeachable reputation; unimpeachable testimony.
Thesaurus Entries
Christian, above suspicion, absolute, actual, admitting no question, believable, blameless, clean, colorable, conceivable, confirmable, credible, creditable, decent, demonstrable, demonstratable, erect, estimable, ethical, factual, fair, fiduciary, full of integrity, good, high-minded, high-principled, highly respectable, historical, honest, honorable, immaculate, inappealable, incontestable, incontrovertible, inculpable, indisputable, indubitable, inviolate, irrefragable, irrefutable, irreprehensible, irreproachable, irreprovable, just, law-abiding, law-loving, law-revering, manly, moral, noble, plausible, principled, provable, pure, real, reliable, reputable, respectable, right, right-minded, righteous, self-evident, spotless, stainless, sterling, tenable, testable, true-dealing, true-devoted, true-disposing, true-souled, true-spirited, truehearted, trustworthy, trusty, unanswerable, unarraignable, unblamable, unblameworthy, unblemished, uncensurable, unconfutable, uncorrupt, uncorrupted, undefiled, undeniable, unexceptionable, unindictable, unobjectionable, unquestionable, unrefutable, unspotted, unstained, unsullied, untarnished, upright, uprighteous, upstanding, verifiable, virtuous, worthy, worthy of faith, yeomanly