Up in the air (5)
'up in the air' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for uncertain that I've seen before include "In doubt" , "Not definitely known" , "up in the air" , "Not completely confident or sure of" , "Unsure" .)
'up in the air' is the definition.
(aloft means above or overhead)
This is all the clue.
(Other definitions for aloft that I've seen before include "Above - on top" , "in a high position" , "At a considerable height" , "To great height" , "at high altitude" .)