City overcome, without feasible finish (7)
I believe the answer is:
lacquer
'finish' is the definition.
(I've seen this before)
'city overcome without feasible' is the wordplay.
'city' becomes 'LA' (Los Angeles).
'overcome' becomes 'conquer' (synonyms).
'without' suggests deleting specific letters.
'feasible' becomes 'on' (as opposed to 'not on' -unacceptable or unfeasible).
'conquer' with 'on' removed is 'cquer'.
'la'+'cquer'='LACQUER'
(Other definitions for lacquer that I've seen before include "Shellac and alcohol hair spray" , "16 21 [INDIAN IMPORT]" , "Glossy finisher" , "Protective coating for wood" , "protective cover" .)