Harry confused when Ned failed to concentrate (5)

I believe the answer is:

focus

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'to concentrate' is the definition.
(synonyms)

I cannot understand how the rest of the clue works.

(Other definitions for focus that I've seen before include "Cynosure" , "Adjust camera lenses - concentrate" , "Where light-rays meet" , "Spotlight" , "Bull's-eye" .)

I've seen this clue in the Sydney Morning Herald.

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