Possibly golden antique, that is (5)
I believe the answer is:
oldie
'possibly golden' is the definition.
I can't tell whether this defines the answer.
'antique that is' is the wordplay.
'antique' becomes 'old' (similar in meaning).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'old'+'ie'='OLDIE'
Can you help me to learn more?
(Other definitions for oldie that I've seen before include "Venerable person/thing" , "An octogenarian, perhaps" , "Perennially popular song or film, often golden" , "Still popular hit" , "Song of yesteryear" .)