American loudly leaving in a rage, attracting much interest (8)
I believe the answer is:
usurious
'attracting much interest' is the definition.
(usury is lending with very high interest rates)
'american loudly leaving in a rage' is the wordplay.
'american' becomes 'us'.
'loudly' becomes 'f' (A musical term).
'leaving' is a deletion indicator.
'in a rage' becomes 'furious'.
'furious' with 'f' removed is 'urious'.
'us'+'urious'='USURIOUS'
(Other definitions for usurious that I've seen before include "attracting huge interest" , "Relating to money-lending at very high rates" , "Given to charging excessive interest, like Biblical businessman" , "Taking a healthy interest" , "Charging outrageous interest" .)