Fashionable officer, on the whole (2,7)
I believe the answer is:
in general
'on the whole' is the definition.
(I've seen this before)
'fashionable officer' is the wordplay.
'fashionable' becomes 'in' (in can mean fashionable or trendy).
'officer' becomes 'general' (general officer is a kind of officer).
'in'+'general'='IN GENERAL'
(Other definitions for in general that I've seen before include "Mostly" , "More-or-less" , "Commonly" , "Largely" , "for the most part" .)