Hide in empty storehouse on Greek island (7)
I believe the answer is:
secrete
'hide' is the definition.
(I know that secrete is a more specific form of hide)
'empty storehouse on greek island' is the wordplay.
'empty' means to remove the middle letters.
'on' is a charade indicator (letters next to each other).
'greek island' becomes 'crete' (Crete is a Greek island).
'storehouse' with its middle removed is 'se'.
'se'+'crete'='SECRETE'
'in' is the link.
(Other definitions for secrete that I've seen before include "harbour" , "Place out of sight, hide" , "(Of gland) produce (a substance)" , "squirrel" , "Form substance for use within body, as liver does bile" .)