German city individual making all-out effort (5)
I believe the answer is:
trier
This clue is a double definition.
'german city' is the first definition.
(I've seen this before)
'individual making all-out effort' is the second definition.
(someone who tries)
(Other definitions for trier that I've seen before include "one hears" , "One always ready to have a go" , "one never giving up" , "One has a crack" , "Test" .)