Seeing nothing wrong in being smart (7)
I believe the answer is:
soignee
'being smart' is the definition.
(thesaurus)
'seeing nothing wrong' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'wrong' indicates anagramming the letters.
'seeing'+'o'='seeingo'
'seeingo' with letters rearranged gives 'SOIGNEE'.
'in' acts as a link.
(Other definitions for soignee that I've seen before include "Of a Frenchwoman, wellgroomed and sophisticated" , "smart" , "No siege laid to well-groomed, classy kind of woman" , "Elegant female" .)