Swinger on wire crossing the raging Tiber (9)

I believe the answer is:

libertine

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'swinger' is the definition.
(thesaurus)

'wire crossing the raging tiber' is the wordplay.
'wire' becomes 'line' (I can't explain this - if you can you should believe this answer much more).
'crossing' is an insertion indicator (to cross can mean to go over or around).
'the raging' indicates an anagram.
'tiber' anagrammed gives 'ibert'.
'line' going around 'ibert' is 'LIBERTINE'.

'on' acts as a link.

Can you help me to learn more?

(Other definitions for libertine that I've seen before include "Person who live immorally - sounds free" , "Morally dissolute" , "Rake" , "reprobate" , "Sensually indulgent person" .)

I've seen this clue in the Sydney Morning Herald.

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