He keeps attempting to name a German city (5)

I believe the answer is:

trier

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'german city' is the definition.
(Trier is a city in Germany)

I don't understand how the rest of the clue works.

(Other definitions for trier that I've seen before include "German town, the capital of the northern empire in Roman times" , "town in Germany" , "One has a crack" , "Persevering type" , "One who doesn't give up - judge?" .)

I've seen this clue in the Evening Standard.

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