Curly-leafed cabbage (4)
I believe the answer is:
kale
'curly-leafed cabbage' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for kale that I've seen before include "Cabbage variety" , "Cabbage in a lake" , "Crinkle-leaf cabbage" , "Hardy cabbage" , "(Curly?) cabbage" .)