Cabbagelike vegetable (4)
I believe the answer is:
'cabbagelike vegetable' 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 "Curly-leafed cabbage" , "Something green" , "Hardy cabbage" , "Type of cabbage" , "Cabbage in a lake" .)