Green, everything devoured by female elephant (6)
I believe the answer is:
callow
'green' is the definition.
(I've seen this before)
'everything devoured by female elephant' is the wordplay.
'everything' becomes 'all' (all things).
'devoured by' is an insertion indicator.
'female elephant' becomes 'cow' (a female elephant is called a cow).
'all' going within 'cow' is 'CALLOW'.
(Other definitions for callow that I've seen before include "Young and inexperienced" , "23 [BRIGHTONIAN] actor" , "lacking experience of life" , "Inexperienced or innocent" , "Immature and inexperienced, as youth often is" .)