Tyrant reportedly close to opposition leader (4)

I believe the answer is:

nero

'tyrant' is the definition.
(I have seen 'Roman tyrant ' mean 'nero' so perhaps 'tyrant' could also mean 'nero')

I don't understand how the remainder of the clue works.

(Other definitions for nero that I've seen before include "Roman emperor, d. AD68" , "Roman emperor infamous for his cruelty" , "Imperial Roman fiddler" , "Notorious Roman emperor, d. AD 68" , "Ancient Roman emperor" .)

I've seen this clue in The Guardian.

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