Feel it's what the greenhorn lacks (10)
I believe the answer is:
experience
'feel' is the definition.
(I know that feel is a more specific form of experience)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for experience that I've seen before include "Go through" , "Encounter" , "Knowledge gained over time" , "What one has been through and is supposed to learn from" , "Try" .)