Shortly, shortly (4)
I believe the answer is:
asap
'shortly shortly' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for asap that I've seen before include "Notation meaning without delay, treat as urgent" , "Initials notation meaning with all possible speed" , "At one's earliest convenience" , "Notation meaning with minimum delay" , "Notation or acronym meaning without avoidable delay" .)