unbelievable
adj. B1 Intermediate US //ˌənbəˈɫivəbəɫ// UK //ʌnbɪlˈiːvəbəl// un·be·liev·able
adj. extremely surprising or difficult to believe. You use this when something is so good, bad, or strange that it feels like it cannot be true.
adj. too improbable or extraordinary to be believed; often used as an intensifier for extreme qualities. Typically gradable, though it can function as an absolute adjective in literal contexts.
The view from the top of the mountain is unbelievable.
It is unbelievable that the team managed to win after being three goals down at halftime.
The witness provided an unbelievable account of the events, which led the jury to question the reliability of the entire prosecution case.
From un- + believable.
Usage
Often used as a gradable adjective with 'absolutely' or 'totally' for emphasis.