Green bird born in French island (8)
I believe the answer is:
gullible
'green' is the definition.
('gullible' can be a synonym of 'green')
'bird born in french island' is the wordplay.
'bird' becomes 'gull' (gull is a kind of bird**).
'born' becomes 'b'.
'in' is an insertion indicator.
'french island' becomes 'ile' (French for 'island').
'b' placed inside 'ile' is 'ible'.
'gull'+'ible'='GULLIBLE'
(Other definitions for gullible that I've seen before include "Easily deceived, naive" , "Credulous, easily deceived" , "Easily fooled" , "Easily taken in, too quick to believe" , "Naive and easily tricked" .)