A loud manner, in business? (6)
I believe the answer is:
affair
'business?' is the definition.
(I've seen this before)
'a loud manner' is the wordplay.
'loud' becomes 'ff' (musical abbreviation for fortissimo, very loud).
'manner' becomes 'air' (air can mean someone's manner or character).
'a'+'ff'+'air'='AFFAIR'
'in' is the link.
(Other definitions for affair that I've seen before include "Concern,matter" , "Matter or concern, perhaps of the heart" , "A function or a romance" , "Concern (maybe extra-marital?)" , "Thing to be done with raffia" .)