Italian leaders, taken aback about river, repressed pagan deity (7-3)

I believe the answer is:

serpent-god

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'italian leaders taken aback about river repressed' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'pagan deity' is the wordplay.
'pagan' becomes 'serpent' (I can't explain this - if you can you should give a lot more credence to this answer).
'deity' becomes 'god' (a deity is a god or divine being).
'serpent'+'god'='SERPENT-GOD'

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