Keep in drawer (5)
I believe the answer is:
tower
I believe this is a double definition.
'keep' is the first definition.
(keep can mean a fortified structure)
'drawer' is the second definition.
(I've seen this before)
'in' acts as a link.
(Other definitions for tower that I've seen before include "Skyscraper" , "Rise to great height" , "tractor, perhaps" , "famous prison" , "Tall column" .)