Old scoundrel coming to old port with something sung (8)
I believe the answer is:
oratorio
'something sung' is the definition.
I can't judge whether this definition defines the answer.
'old scoundrel coming to old port' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'scoundrel' becomes 'rat' (both can mean a dishonourable person).
'coming to' is a charade indicator (letters next to each other).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'port' becomes 'rio' (Rio de Janeiro is a port).
'o'+'rat'+'o'+'rio'='ORATORIO'
'with' acts as a link.
Can you help me to learn more?
(Other definitions for oratorio that I've seen before include "Musical composition for voices and orchestra based on a religious text" , "Work for many performers" , "Comprehensive music" , "Large choral work" , "Outlying part of city" .)