up in the air

1. 1.

   very uncertain

   “left everything up in the air”

   Similaruncertain
2. 2.

   not yet determined

   “plans are still up in the air”

   Similaruncertain

Questions about up in the air

What does up in the air mean?

up in the air means "very uncertain". That is the primary sense; the word has 2 in total, listed in full on this page.

Is up in the air a common word?

up in the air is banded "Uncommon" — turns up in careful writing rather than conversation. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.