Soar without an engine (5)
I believe the answer is:
glide
'soar without an engine' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for glide that I've seen before include "Fly through the air with the greatest of ease" , "Skate" , "Move gracefully" , "Skim" , "Fly without power" .)