improbably

Từ điển WordNet v3.1 - WordNet Dictionary

adverb

not easy to believe
- behind you the coastal hills plunge to the incredibly blue sea backed by the Turkish mountains
• Syn:
incredibly, implausibly, unbelievably
• Ant:
believably (for: unbelievably), credibly (for: incredibly)
• Derived from adjective:
unbelievable (for: unbelievably), implausible (for: implausibly), improbable, incredible (for: incredibly)