unbelievableEnglishOxford English Thesaurusunbelievable adjective your audacity is simply unbelievable: incredible, beyond belief, difficult to believe, scarcely credible, inconceivable, unthinkable, unimaginable; unconvincing, far-fetched, implausible, improbable, impossible; informal hard to swallow, mind-boggling, mind-blowing. ▷antonyms believable, credible.unbelievable Oxford Dictionary of English