A friend with a lot of regular business in Arab city (3,5)
I believe the answer is:
abu dhabi
'arab city' is the definition.
(capital of the United Arab Emirates)
'a friend with a lot of regular business' is the wordplay.
'a friend' becomes 'bud' (shortly for buddy).
'with' says to put letters next to each other.
'lot of' means to remove the last letter (I've seen 'lots of' mean this (the majority of the word)).
'regular business' becomes 'habit' (business or action done habitually).
'habit' with its final letter taken off is 'habi'.
'bud' put after 'a' is 'abud'.
'abud'+'habi'='ABU DHABI'
'in' acts as a link.
(Other definitions for abu dhabi that I've seen before include "sheikhdom!" , "Asian capital" , "Persian Gulf emirate" , "Federal capital of the United Arab Emirates" , "foreign land" .)