Mostly wealthy, with a good deal of passion for American economist (7)

'economist' is the definition.
(I've seen this before)

'mostly wealthy with a good deal of' is the wordplay.
'mostly' means to remove the last letter (most but not all of the word).
'wealthy' becomes 'rich' (similar in meaning).
'with' says to put letters next to each other.
'good deal' becomes 'rd' (I am not sure about this - if you are sure you should believe this answer much more).
'of' becomes 'o''.
'rich' with its last letter taken off is 'ric'.
'ric'+'a'+'rd'+'o'='RICARDO'

'passion for american' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.

Can you help me to learn more?