Undisclosed military rank (7)

I believe the answer is:

private

This clue is a double definition.

'undisclosed' is the first definition.
(thesaurus)

'military rank' is the second definition.
(I know this)

(Other definitions for private that I've seen before include "Clandestine" , "See 16" , "Lowest ranking soldier" , "Not openly shared" , "Army three Dn" .)

I've seen this clue in The Telegraph, The Globe and Mail, The Sun and The Guardian.

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