Extortion in America? Arab chief audibly unhappy (9)
I believe the answer is:
shakedown
'extortion in america? arab' is the definition.
'shakedown' can be an answer for 'extortion' (shakedown is a kind of extortion). I am not sure about the 'in america? arab' bit.
'chief audibly unhappy' is the wordplay.
'chief audibly' becomes 'shake' (I am not sure about this - if you are sure you should believe this answer much more).
'unhappy' becomes 'down' (I've seen this before).
'shake'+'down'='SHAKEDOWN'
Can you help me to learn more?
(Other definitions for shakedown that I've seen before include "Overcharge villainously" , "Makeshift bed" , "extortion" , "improvised bed" .)