Ruler sometimes breathless (5)

I believe the answer is:

rajah

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'ruler' is the definition.
(I have seen 'Indian ruler ' mean 'rajah' so perhaps 'ruler' could also mean 'rajah')

I cannot understand how the remainder of the clue works.

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(Other definitions for rajah that I've seen before include "Asian ruler" , "Indian king or prince" , "Hindu ruler" , "Former Indian ruler" , "Royal Indian male" .)

I've seen this clue in the Evening Standard.

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