It's her fault I'm gone! (6)
I believe the answer is:
imogen
'it's her' is the definition.
(I've seen this before)
'fault i'm gone' is the wordplay.
'fault' indicates anagramming the letters (a faulty spelling).
'im'+'gone'='imgone'
'imgone' anagrammed gives 'IMOGEN'.
(Other definitions for imogen that I've seen before include "Girl's name; go mine (anagram)" , "Shakespearean king's daughter" , "identity of Cymbeline's daughter" , "Woman" , "Daughter of Cymbeline in Shakespeare's play" .)