Whistleblower holding back accessories (5)
I believe the answer is:
belts
'accessories' is the definition.
(belt is a kind of accessory)
'whistleblower holding back' is the wordplay.
'holding' indicates a hidden word.
'back' says the letters should be written in reverse.
'stleb' can be found hidden inside 'whistleblower'.
'stleb' back-to-front is 'BELTS'.
(Other definitions for belts that I've seen before include "Moves quickly" , "Waist bands" , "Leather bands" , "Hits" , "Fat controllers perhaps" .)