Dignify letterhead with empty line? (7)

I believe the answer is:

ennoble

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'dignify' is the definition.
(synonyms)

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

(Other definitions for ennoble that I've seen before include "Elevate in rank" , "Turn to peer" , "Distinguish" , "Elevate with a title" , "Elevate to peerage" .)

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

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