Capital! Old guy playing the field (5)

I believe the answer is:

romeo

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'guy playing the field' is the definition.
I can't tell whether this defines the answer.

'capital old' is the wordplay.
'capital' becomes 'rome' (capital of Italy).
'old' becomes 'o' (abbreviation).
'rome'+'o'='ROMEO'

Can you help me to learn more?

(Other definitions for romeo that I've seen before include "Code word for the letter R" , "Tragic Shakespeare hero" , "Juliet's swain" , "24's lover" , "Shakespearean lover" .)

I've seen this clue in The Guardian.

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