Reputation in theatre now negligible (6)
I believe the answer is:
renown
'reputation' is the definition.
(thesaurus)
'in theatre now negligible' is the wordplay.
'in' says the answer is hidden in the clue.
'RENOWN' can be found hidden inside 'theatre now negligible'.
(Other definitions for renown that I've seen before include "High reputation, fame" , "Good reputation" , "Fame and public acclamation" , "Fame and distinction" , "Plane's maximum width" .)