In favour of German criminal (6)
I believe the answer is:
forger
'criminal' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'in favour of german' is the wordplay.
'in favour of' becomes 'for' (being for a particular cause).
'german' becomes 'ger' (abbreviation).
'for'+'ger'='FORGER'
Can you help me to learn more?
(Other definitions for forger that I've seen before include "Person who makes phoney bank notes" , "Criminal who makes dud bank notes" , "who makes a lot of money?" , "Maker of false bank-notes" , "Ironworker" .)