1.
If you say that something is unbelievable, you are emphasizing that it is very good, impressive, intense, or extreme.
His guitar solos are just unbelievable...
It was an unbelievable moment when Chris won the gold medal.
= incredible
ADJ [emphasis]
• unbelievably
Our car was still going unbelievably well...
He beamed: 'Unbelievably, we have now made it to the final twice.'
= incredibly
ADV: ADV with cl/group
2.
You can use unbelievable to emphasize that you think something is very bad or shocking.
I find it unbelievable that people can accept this sort of behaviour...
= incredible
ADJ: oft it v-link ADJ that [emphasis]
• unbelievably
What you did was unbelievably stupid...
Unbelievably, our Government are now planning to close this magnificent institution.
= incredibly, amazingly
ADV: ADV with cl/group
3.
If an idea or statement is unbelievable, it seems so unlikely to be true that you cannot believe it.
I still find this story both fascinating and unbelievable...
I know it sounds unbelievable but I never wanted to cheat.
= incredible
ADJ
• unbelievably
Lainey was, unbelievably, pregnant again...
ADV: ADV with cl/group