Legendary couple of leaders of fascist movement usurped? (6)

I believe the answer is:

famous

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'legendary' is the definition.
(thesaurus)

I can't explain the rest of the clue.

(Other definitions for famous that I've seen before include "Illustrious" , "Known-of widely" , "Renowned, noted" , "Renowned, celebrated" , "Widely known and notable" .)

I've seen this clue in the Irish Times.

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