The antonyms for "un attested" include words like "validated," "corroborated," "proven," and "verified." These terms indicate that an assertion or claim has been supported by evidence or witnesses, and can therefore be considered reliable and trustworthy. Other antonyms for "un attested" might include words like "established," "confirmed," "acknowledged," or "accepted," which similarly suggest that something has been verified or proven true. In contrast, synonyms for "un attested" might include words like "unverified," "unproven," "dubious," or "suspect," indicating that an assertion lacks sufficient evidence or credibility.