Hide leak (7)
I believe the answer is:
secrete
I believe this clue is a double definition.
'hide' is the first definition.
(I've seen this before)
'leak' is the second definition.
(thesaurus)
(Other definitions for secrete that I've seen before include "Hide - discharge" , "harbour" , "Cache" , "Hold and send out substance into the body as gland does" , "(Of gland) produce (a substance)" .)