It reversed one German link (3-2)
I believe the answer is:
tie-in
'link' is the definition.
(I know that link can be written as tie-in)
'it reversed one german' is the wordplay.
'reversed' shows that the letters should be reversed in order.
'one german' becomes 'ein' ('one' in German).
'it' reversed gives 'ti'.
'ti'+'ein'='TIE-IN'
(Other definitions for tie-in that I've seen before include "Agree with" , "Coordinate" , "Association, connection" , "Something linked to another item or event" , "Related item" .)