Wealthy earl in the German state (5)
I believe the answer is:
reich
'german state' is the definition.
(as in the Third Reich)
'wealthy earl in' is the wordplay.
'wealthy' becomes 'rich' (similar in meaning).
'earl' becomes 'e'.
'in' means one lot of letters goes inside another.
'rich' placed around 'e' is 'REICH'.
'the' acts as a link.
(Other definitions for reich that I've seen before include "US composer" , "Old German state" , "State no longer" , "The German state during the Nazi regime was the third one" , "Hitler's was the Third" .)