Sarcastic piece in German (6)
I believe the answer is:
'sarcastic' is the definition.
(similar in meaning)
'piece in german' is the wordplay.
'piece' becomes 'bit' (synonyms).
'german' becomes 'g' (abbreviation).
(Other definitions for biting that I've seen before include "Painful or stinging" , "Sarcastic; very cold" , "(Of wit) harsh, cruel" , "Acerbic" , "Mordant" .)