Accessory involved in sex trafficking (5)
I believe the answer is:
extra
'accessory' is the definition.
(I've seen this before)
'involved in sex trafficking' is the wordplay.
'involved in' indicates a hidden word.
'EXTRA' is hidden within 'sex trafficking'.
(Other definitions for extra that I've seen before include "Something additional or bit player in movie" , "Minor person screened" , "Score not made by 34 [CRICKETER]" , "I may carry spear" , "Actor in non-speaking role" .)