Bitterness from defeated Germans (4)
I believe the answer is:
edge
'bitterness' is the definition.
(thesaurus)
'from defeated germans' is the wordplay.
'from' says the answer is hidden in the clue.
'EDGE' is hidden within 'defeated germans'.
(Other definitions for edge that I've seen before include "Intense quality; limit" , "Sharp ridge" , "Final line" , "Margin, extremity" , "small advantage" .)