1. Very uncertain
   "left everything up in the air" 
2. Not yet determined
   "plans are still up in the air"

See also: uncertain

• conformably
• conformal
• conformal projection
• conformance
• conformant
• conformation
• conformational entropy
• conformer
• conforming
• conformism
• conformist
• conformity
• confound
• confounded
• confoundedly
• confounding
• confraternity
• confront
• confrontation
• confrontational
• confrère
• Confucian
• Confucianism
• Confucianist
• Confucius