Hardy green ring from King Lear (4)
I believe the answer is:
kale
'hardy green ring' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'king lear' is the wordplay.
'king' becomes 'k'.
'lear' becomes 'ale' (I can't explain this - if you can you should believe this answer much more).
'k'+'ale'='KALE'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for kale that I've seen before include "Crinkle-leaf cabbage" , "Hardy cabbage" , "Type of cabbage" , "Cabbage variety" , "Curly-leafed cabbage" .)