unbelievable
un-be-liev-a-ble
adjective
Too surprising, extraordinary, or difficult to believe; often used for emphasis.
"The team's victory was absolutely unbelievable."
Thesaurus
Synonyms: unlikely, implausible, unconvincing, improbable, astounding, undreamed, undreamed of, incredible, marvellous, marvelous, tall, undreamt of
Antonyms: believable, credible