Care for business (7)
I believe the answer is:
concern
This clue is a double definition.
'care' is the first definition.
(synonyms)
'business' is the second definition.
(eg 'none of your concern', 'none of your business')
'for' acts as a link.
(Other definitions for concern that I've seen before include "Feeling of anxiety or sympathy" , "Have something to do with" , "Business - anxiety" , "Disquiet" , "Firm - interest" .)