Dividing partition; conceal (6)
I believe the answer is:
screen
I believe this is a double definition.
'dividing partition' is the first definition.
(I've seen this before)
'conceal' is the second definition.
(I've seen this in another clue)
(Other definitions for screen that I've seen before include "Sheltering row of trees" , "Conceal; show (a film)" , "TV surface" , "Surface, for showing movies say" , "It can serve both to conceal and to show something" .)