Hail new German nemesis (7)
I believe the answer is:
avenger
'nemesis' is the definition.
(I've seen this in another clue)
'hail new german' is the wordplay.
'hail' becomes 'ave' (greeting in Latin).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'german' becomes 'ger' (abbreviation).
'ave'+'n'+'ger'='AVENGER'
(Other definitions for avenger that I've seen before include "One who exacts reparation for a wrong" , "One settles score" , "One bent on retaliation." , "Inflicter of retribution" , "Bringer of retribution" .)