Exposed debt collector back in action (7)
I believe the answer is:
denuded
'exposed' is the definition.
(thesaurus)
'debt collector back in action' is the wordplay.
'debt collector' becomes 'dun' (historical term for a debt collector).
'back' says the letters should be written backwards.
'in' indicates putting letters inside.
'action' becomes 'deed' (deed is a kind of action).
'dun' back-to-front is 'nud'.
'nud' placed inside 'deed' is 'DENUDED'.
(Other definitions for denuded that I've seen before include "Laid bare" , "Stripped" .)