I leave European city as champ (5)
I believe the answer is:
munch
'champ' is the definition.
(both can mean to bite)
I don't understand the rest of the clue.
(Other definitions for munch that I've seen before include "champ" , "Chew steadily and vigorously" , "Eat audibly; painter" , "Edvard -, Norwegian artist (The Scream)" , "Eat steadily; Norw. artist" .)