Show or conceal (6)
I believe the answer is:
screen
I believe this is a double definition.
'show' is the first definition.
(screen can mean to show a film)
'conceal' is the second definition.
(I've seen this in another clue)
'or' acts as a link.
(Other definitions for screen that I've seen before include "Room divider" , "Shield - broadcast" , "Conceal; test" , "Filter the mobile partition" , "Cinema feature" .)