Rich American alcoholic (4)
I believe the answer is:
lush
This clue might be a double definition.
'rich' is the first definition.
(similar in meaning)
'american alcoholic' is the second definition.
'lush' can be an answer for 'alcoholic' (synonyms). I am unsure of the 'american' bit.
Can you help me to learn more?
(Other definitions for lush that I've seen before include "Luxuriant; very rich" , "one mortal too often" , "he drinks a lot!" , "Lavish - boozer" , "Succulent - heavy drinker" .)