Arab leader sounds alarm (6)

I believe the answer is:

sheikh

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'arab leader' is the definition.
(I've seen this in another clue)

I cannot understand how the remainder of the clue works.

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(Other definitions for sheikh that I've seen before include "Head of Arab tribe, village etc" , "Weapons maker" , "leader of Arabs" , "Broadcast upset" , "Disturbance of the peace; brawl" .)

I've seen this clue in The Times and The Sunday Times.

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