Regard as a business (7)
I believe the answer is:
concern
I believe this clue is a double definition.
'regard' is the first definition.
(thesaurus)
'a business' is the second definition.
('concern' can be a synonym of 'business')
'as' acts as a link.
(Other definitions for concern that I've seen before include "Affair" , "Relate to; care" , "Business - worry" , "Feeling of anxiety or sympathy" , "Disquiet" .)