Someone to do business with? (7)
I believe the answer is:
partner
I believe this is a double definition.
'someone' is the first definition.
(partner is a kind of someone)
'do business with?' is the second definition.
(thesaurus)
'to' is the link.
(Other definitions for partner that I've seen before include "Husband or wife" , "Mate or collaborator" , "Either one of a couple" , "Companion at bridge, dance, or home" , "Ally" .)