Cold line, see, turning up in a love song (7)
I believe the answer is:
calypso
'a love song' is the definition.
(thesaurus)
'cold line see turning up in' is the wordplay.
'cold line' becomes 'calo' (I can't explain this - if you can you should believe this answer much more).
'see' becomes 'spy' (spy can mean to see or observe).
'turning up' says the letters should be written in reverse.
'in' means one lot of letters goes inside another.
'spy' back-to-front is 'yps'.
'calo' placed around 'yps' is 'CALYPSO'.
Can you help me to learn more?
(Other definitions for calypso that I've seen before include "sarcastic air" , "West Indian ballad rhythm" , "A number of West Indians" , "West Indian ballad - Homerian sea nymph" , "W. Indian ballad" .)