Break the news (4)
I believe the answer is:
'break the news' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tell that I've seen before include "Reveal - command" , "William .... was legendary Swiss hero-archer" , "Relate; Swiss hero" , "William . . . . was a legendary Swiss archer" , "Instruct" .)