Airborne soldier (4)
I believe the answer is:
para
'airborne soldier' is the definition.
(paratrooper)
This is the entire clue.
(Other definitions for para that I've seen before include "Soldier dropping to earth" , "A block of text; an airborne soldier (abbrs.)" , "Brazilian state" , "Soldier who jumps to order? (abbr)" , "Soldier (shortened)" .)