In French street, go back for wrong 'un (5)
I believe the answer is:
rogue
'wrong 'un' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'in french street go back' is the wordplay.
'in' is an insertion indicator.
'french street' becomes 'rue' (French for street or road).
'back' shows that the letters should be reversed in order.
'go' back-to-front is 'og'.
'rue' enclosing 'og' is 'ROGUE'.
'for' is the link.
Can you help me to learn more?
(Other definitions for rogue that I've seen before include "Miscreant" , "Impish, likeable person" , "Profligate" , "Prankster" , "Mischievous person" .)