Edge inside bunker briefly (4)
I believe the answer is:
kerb
'edge' is the definition.
(I know that kerb is a type of edge)
'inside bunker briefly' is the wordplay.
'inside' indicates a hidden word.
'KERB' is hidden within 'bunker briefly'.
(Other definitions for kerb that I've seen before include "Edge of road" , "Stone edging to footpath" , "Side of road" , "Pancakes" , "stone by the way" .)