Writer and poet ultimately wanting jewellery (7)
I believe the answer is:
pendant
'jewellery' is the definition.
'writer and poet ultimately wanting' is the wordplay.
'writer' becomes 'pen' (I've seen this before).
'and' means one lot of letters go next to another.
'poet' becomes 'dante' (Dante is an example).
'ultimately wanting' means to remove the last letter (wanting can mean lacking).
'dante' with its last letter taken away is 'dant'.
'pen'+'dant'='PENDANT'
(Other definitions for pendant that I've seen before include "earring, say" , "Panted after learned one" , "Ornament hanging from a piece of jewellery" , "item suspended" , "Hanging light" .)