1. not easy to believe
2. in an unbelievable manner
- he was unbelievably angry
Sentences with unbelievably as an adverb:
- He gestured unbelievably. Everyone knew he was faking being sick.
- His face turned unbelievably blue. We realized he was actually choking.
- Unbelievably, Rudy saved the man's life but got sued for breaking two of his ribs.