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

See also: uncertain

• Melinae
• meliorate
• melioration
• meliorative
• meliorism
• meliorist
• Meliphagidae
• melisma
• Melissa
• Melissa officinalis
• Melkite
• Mellaril
• melliferous
• mellifluent
• mellifluous
• mellisonant
• Mellivora
• Mellivora capensis
• Mellon
• mellow
• mellow out
• mellowed
• mellowing
• mellowingly
• mellowly