Furniture item useful to an actor (7)
I believe the answer is:
dresser
This clue is a triple definition!
'furniture' is the first definition.
(I know that dresser is a type of furniture)
'item' is the second definition.
(I have seen 'Item of furniture' mean 'dresser' so perhaps 'item' could also mean 'dresser')
'useful to an actor' is the third definition.
(staff member who dresses an actor)
(Other definitions for dresser that I've seen before include "big chest" , "Surgeon's assistant" , "Piece of kitchen furniture" , "helps actor get ready" , "One chiding" .)