Livestock eats everything green (6)
I believe the answer is:
callow
'green' is the definition.
(I've seen this before)
'livestock eats everything' is the wordplay.
'livestock' becomes 'cow' (I can't explain this - if you can you should give a lot more credence to this answer).
'eats' indicates putting letters inside.
'everything' becomes 'all' (all things).
'cow' going around 'all' is 'CALLOW'.
Can you help me to learn more?
(Other definitions for callow that I've seen before include "Jejune" , "23 [BRIGHTONIAN] actor" , "Green" , "Simon ---, actor; immature" , "Inexperienced or unsophisticated, as a youth say" .)