Stale or unopened (3)
I believe the answer is:
old
'stale' is the definition.
(synonyms)
'or unopened' is the wordplay.
'or' becomes 'gold' ('or' is the heraldic term for gold).
'unopened' means to remove the first letter (without opening letter).
'gold' with its initial letter removed is 'OLD'.
(Other definitions for old that I've seen before include "Advanced in years" , "Former; aged" , "Senescent" , "At an early stage - at a late stage" , "No longer young" .)