Usually at home - army officer (2,7)
I believe the answer is:
in general
'usually' is the definition.
(thesaurus)
'home army officer' is the wordplay.
'home' becomes 'in' ('he's home' can mean 'he's in').
'army officer' becomes 'general' (I've seen this before).
'in'+'general'='IN GENERAL'
'at' is the link.
(Other definitions for in general that I've seen before include "Largely" , "Not particularly" , "Where soldiers should have faith" , "for the most part" , "More-or-less" .)