Wanda's child sins terribly in old Hawaii (8,7)
I believe the answer is:
sandwich islands
'old hawaii' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.
'wanda's child sins terribly' is the wordplay.
'terribly' indicates an anagram.
'wandas'+'child'+'sins'='wandaschildsins'
'wandaschildsins' anagrammed gives 'SANDWICH ISLANDS'.
'in' acts as a link.
Can you help me to learn more?
(Another definition for sandwich islands that I've seen is " Hawaii a while back".)