Hide or show (6)
I believe the answer is:
screen
This clue is a double definition.
'hide' is the first definition.
(I've seen this in another clue)
'show' is the second definition.
(screen can mean to show a film)
'or' is the link.
(Other definitions for screen that I've seen before include "Movable partitions" , "Show pictures on the surface" , "Surface on which to project pictures" , "Conceal; show (a film)" , "Block out" .)