Artist and fashion designer not finishing off set (5)
I believe the answer is:
radio
'set' is the definition.
(radio is a kind of set)
'artist and fashion designer not finishing off' is the wordplay.
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'and' says to put letters next to each other.
'fashion designer' becomes 'dior' (Christian Dior).
'not finishing off' means to remove the last letter.
'dior' with its final letter taken away is 'dio'.
'ra'+'dio'='RADIO'
(Other definitions for radio that I've seen before include "Transistor" , "means of communication" , "Receiving apparatus" , "Broadcast receiver" , "Sound receiver" .)