Courage and instinct about politician no one backed (8)
I believe the answer is:
gumption
'courage' is the definition.
(thesaurus)
'instinct about politician no one backed' is the wordplay.
'instinct' becomes 'gut' (**).
'about' means one lot of letters goes inside another.
'politician' becomes 'mp'.
'one' becomes 'i' (Roman numeral).
'backed' is a reversal indicator.
'no'+'i'='noi'
'noi' in reverse letter order is 'ion'.
'gut' going around 'mp' is 'gumpt'.
'gumpt'+'ion'='GUMPTION'
'and' is the link.
(Other definitions for gumption that I've seen before include "Informal drive and initiative" , "To impugn (anag) - common sense" , "Shrewdness, common-sense" , "Fortitude and determination" , "Sense; courage" .)