Nora's wild horse (4)
I believe the answer is:
roan
'horse' is the definition.
(I know that roan is a type of horse)
'nora's wild' is the wordplay.
'wild' is an anagram indicator.
'nora' with letters rearranged gives 'ROAN'.
(Other definitions for roan that I've seen before include "Reddish-coloured horse" , "Bay spotted" , "Two-colour horse" , "Horse with a brownish coat sprinkled with grey" , "Horse with a coat of mixed colour" .)