Sikh topper but no head is citified (5)

I believe the answer is:

urban

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'is citified' is the definition.
(similar in meaning)

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

(Other definitions for urban that I've seen before include "Name adopted by eight popes: built-up" , "Belonging to a city" , "away from the country?" , "Civic" , "One of eight popes" .)

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

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