Whin (5)
I believe the answer is:
gorse
'whin' is the definition.
(I know that whin can be written as gorse)
This is the entire clue.
(Other definitions for gorse that I've seen before include "furs, say" , "Prickly shrub, furze, whin" , "Spiky shrub" , "Spiny yellow-flowered shrub" , "Moorland shrub" .)