Sheltered guardian of valued goods (4)
I believe the answer is:
safe
'sheltered' is the definition.
(synonyms)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for safe that I've seen before include "Metal box for security" , "Strongbox; secure" , "Reliable" , "Uninjured, secure" , "Secure and protected" .)