A loud "Show business" (6)
I believe the answer is:
affair
'business' is the definition.
(I've seen this in another clue)
'a loud show' is the wordplay.
'loud' becomes 'ff' (musical abbreviation for fortissimo, very loud).
'show' becomes 'air' (both can mean broadcast).
'a'+'ff'+'air'='AFFAIR'
(Other definitions for affair that I've seen before include "Secret romance" , "Matter or concern, perhaps of the heart" , "Former Belgian coin" , "Singular business" , "A romantic intrigue" .)