Business concern (6)
I believe this clue is a double definition.
'business' is the first definition.
(thesaurus)
'concern?' is the second definition.
(concern is a kind of interest)
(Other definitions for interest that I've seen before include "Excite the curiosity of (someone)" , "Arouse curiosity" , "Share in an undertaking" , "Profit" , "Return" .)
But I've got no explanation for this one! Could you help me understand?
(Other definitions for affair that I've seen before include "scandal" , "Concern,matter" , "Amour" , "Extramarital activity" , "Romantic relationship between two unmarried people" .)