i-adjective
unbelievable; incredible; implausible
Expresses that something is so surprising, extreme, or unlikely that it is hard to believe. Often used as an exclamation.
See also: 信じる (しんじる)
彼が試験に合格したなんて信じられない。
I can't believe he passed the exam.
信じられないほど美しい景色だった
It was an unbelievably beautiful view.