The old man's voting against that Spanish neighbour (7)
I believe the answer is:
paisano
'spanish neighbour' is the definition.
The definition suggests a singular noun which matches the answer.
'the old man's voting against' is the wordplay.
'the old man's voting' becomes 'paisa' (I can't explain this - if you can you should give a lot more credence to this answer).
'against' becomes 'no'.
'paisa'+'no'='PAISANO'
'that' acts as a link.
Can you help me to learn more?
(Other definitions for paisano that I've seen before include "American friend" , "buddy" .)