His achievement in the competition was unbelievable.
performance
Frequency:
55
%
His performance in the play was truly unbelievable.
talent
Frequency:
50
%
Her talent for painting was truly unbelievable.
feat
Frequency:
45
%
Their feat of climbing the mountain was unbelievable.
Idiomatic Expressions for unbelievable
Phrase: unbelievable story
Meaning: a tale that is hard to believe or seems too extraordinary to be true
Usage: He told us an unbelievable story about his encounter with a UFO.