Green leaf I angled back, somewhat (4)
I believe the answer is:
naif
'green' is the definition.
(similar in meaning)
'leaf i angled back somewhat' is the wordplay.
'somewhat' says the answer is hidden in the clue.
'back' is a reversal indicator.
'fian' is hidden in the letters of 'leaf i angled'.
'fian' back-to-front is 'NAIF'.
(Other definitions for naif that I've seen before include "wide-eyed" , "Green" , "Inexperienced" , "Unsophisticated" , "Artless" .)