Back from "The Green Man" (4)
I believe the answer is:
emil
'man' is the definition.
I know nothing about this answer so I can't judge whether this works.
'back from the green' is the wordplay.
'back from' says to take the final letters (the letter at the back of the word).
'green' becomes 'mil' (I am not sure about this - if you are sure you should believe this answer much more).
The final letter of 'the' is 'e'.
'e'+'mil'='EMIL'
Can you help me to learn more?
(Other definitions for emil that I've seen before include "German boy" , "- - Zatopek, Olympic runner" , "French boy's name" .)