Cover skin (4)
I believe the answer is:
hide
I believe this clue is a double definition.
'cover' is the first definition.
(hide is a kind of cover)
'skin' is the second definition.
('hide' can be a synonym of 'skin')
(Other definitions for hide that I've seen before include "Keep quiet" , "Flog" , "Animal's tough skin" , "Pelt; conceal" , "Conceal - skin" .)