Lowest charge by the German opportunist (6,6)
I believe the answer is:
'opportunist' is the definition.
(I know that bottom feeder is a type of opportunist)
'lowest charge by the german' is the wordplay.
'lowest' becomes 'bottom' (synonyms).
'charge by' becomes 'fee' (fee is a kind of charge. I am not sure about the 'by' bit.).
'the german' becomes 'der' ('the' in German).
Can you help me to learn more?