Conceal the skin (4)
I believe the answer is:
hide
I believe this clue is a double definition.
'conceal' is the first definition.
(synonyms)
'skin' is the second definition.
(synonyms)
'the' acts as a link.
(Other definitions for hide that I've seen before include "Animal's tough skin" , "Conceal - skin" , "Mammal's tough skin" , "(Place of) conceal(ment)" , "Keep out of sight" .)