Flag about accountant’s window dressing? (6)
I believe the answer is:
facade
'window dressing?' is the definition.
('facade' can be a synonym of 'window dressing')
'flag about accountant's' is the wordplay.
'flag' becomes 'fade' (I've seen this before).
'about' means one lot of letters goes inside another.
'accountant' becomes 'ca' (abbreviation for chartered accountant).
'fade' enclosing 'ca' is 'FACADE'.
(Other definitions for facade that I've seen before include "Surface of building (6)" , "Front; work by Walton" , "Front presented" , "False front" , "Showy front" .)