What they called Hitler before the war (4)

I believe the answer is:

herr

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'war' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

I don't understand the remainder of the clue.

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(Other definitions for herr that I've seen before include "European guy" , "Mister in German" , "Dieter respectfully addressed" , "German man's title" , "Form of address for German male" .)

I've seen this clue in the Evening Standard.

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