Hardy heroine sets out (4)
I believe the answer is:
tess
'hardy heroine' is the definition.
(in Tess of the d'Urbervilles, Thomas Hardy novel)
'sets out' is the wordplay.
'out' indicates an anagram (out can mean wrong or inaccurate).
'sets' is an anagram of 'TESS'.
(Other definitions for tess that I've seen before include "Hardy's Durbeyfield heroine" , "Hardy female" , "Lady" , "20 heroine" , "- - of the d'Urbervilles" .)