Diana's a new woman
I believe the answer is:
nadia
'woman' is the definition.
'diana's a new' is the wordplay.
'a new' is an anagram indicator.
'diana' is an anagram of 'NADIA'.
(Other definitions for nadia that I've seen before include "___ Comaneci, Romanian-born American gymnast" , "(Originally Russian) female name (reverse of Irish male name)" , "___ Comaneci, Romanian gymnast" , "Foreign woman" , "Name of girl" .)