Politician briefly on a roll — representing a street urchin (10)
I believe the answer is:
ragamuffin
'street urchin' is the definition.
(thesaurus)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for ragamuffin that I've seen before include "Waif" , "Poor mite" , "Unkempt, disreputable child" , "Tatterdemalion" , "One got up badly" .)