A jewelled headdress - an artist takes it back (5)
I believe the answer is:
tiara
'a jewelled headdress' is the definition.
(I know that tiara is a type of jewelled headdress)
'an artist takes it back' is the wordplay.
'an' becomes 'a'.
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'takes' is a charade indicator (letters next to each other).
'back' shows that the letters should be reversed in order.
'a'+'ra'+'it'='arait'
'arait' back-to-front is 'TIARA'.
(Other definitions for tiara that I've seen before include "Woman's crescent-shaped ornamental headdress" , "pope may have been topped by one" , "Pope's triple-tiered crown" , "Jewelled hair-band" , "Jewelled head band" .)