Silver not from the right South Pacific country (5)
I believe the answer is:
tonga
'pacific country' is the definition.
(country in the Pacific Ocean)
'silver not from the right' is the wordplay.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'from the right' shows that the letters should be reversed in order.
'ag'+'not'='agnot'
'agnot' backwards is 'TONGA'.
'south' acts as a link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for tonga that I've seen before include "SW Pacific monarchy" , "Pacific island state" , "transport" , "Pacific Ocean kingdom" , "Polynesian Kingdom" .)