Show shield (6)
I believe the answer is:
screen
I believe this clue is a double definition.
'show' is the first definition.
(screen can mean to show a film)
'shield' is the second definition.
(synonyms)
(Other definitions for screen that I've seen before include "Partition; test suitability" , "Show a motion picture (of)" , "Test for the presence of disease or infection, in the cinema?" , "Mask" , "Block out" .)