Deal with business issue (7)
I believe the answer is:
concern
I believe this is a triple definition!
'deal with' is the first definition.
(eg a book concerning or dealing with a topic)
'business' is the second definition.
(eg 'none of your concern', 'none of your business')
'issue' is the third definition.
(both can mean a problem or difficulty)
(Other definitions for concern that I've seen before include "Feeling of anxiety or sympathy" , "Affair" , "Firm - interest" , "Business - anxiety" , "Relate to; anxiety" .)