Dine out on American cash, it's obscene! (8)
I believe the answer is:
indecent
'obscene' is the definition.
('indecent' can be similar in meaning to 'obscene')
'dine out on american cash' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'on' means one lot of letters go next to another.
'american cash' becomes 'cent'.
'dine' with letters rearranged gives 'inde'.
'inde'+'cent'='INDECENT'
'it's' is the link.
(Other definitions for indecent that I've seen before include "not appropriate" , "Offending against modesty, obscene" , "Rude, improper" , "Immodest or obscene" , "Indecorous" .)