Border protection (5)
I believe the answer is:
apron
I believe this clue is a double definition.
'border' is the first definition.
(apron can mean a border or covering)
'protection' is the second definition.
(protective garment)
(Other definitions for apron that I've seen before include "Domestic protection" , "Space in front of curtain" , "Kitchen garment or airfield area" , "Protective kitchen wear" , "Protective garment (with strings attached!)" .)