1. Not easy to believe
   - incredibly, improbably, implausibly 
2. In an unbelievable manner
   "he was unbelievably angry"

See also: unbelievable

Antonym: believably

• churlishly
• churlishness
• churn
• churn out
• churn up
• churned-up
• churning
• churr
• churrigueresco
• churrigueresque
• chute
• chute-the-chute
• chutney
• chutzpa
• chutzpah
• chutzpanik
• Chuvash
• chylaceous
• chyle
• antennal
• Antennaria
• Antennaria dioica
• Antennaria plantaginifolia
• Antennariidae
• antennary