Put on to hide (6)
I believe the answer is:
screen
This clue is a double definition.
'put on' is the first definition.
(thesaurus)
'hide' is the second definition.
(thesaurus)
'to' is the link.
(Other definitions for screen that I've seen before include "Films are projected onto it" , "Surface, for showing movies say" , "Room divider" , "A film is projected onto it" , "Surface on which pictures are projected in cinemas" .)