Cover up leak (7)
I believe the answer is:
secrete
This could be a double definition.
'cover up' is the first definition.
'secrete' can be an answer for 'cover' (thesaurus). I'm unsure of the 'up' bit.
'leak' is the second definition.
(to secrete is to leak or emit something)
Can you help me to learn more?
(Other definitions for secrete that I've seen before include "Hide away" , "Hide or conceal an object" , "Hide - discharge" , "Cache" , "Hide; as gland does" .)