Create purpose in Green movement? (8)
I believe the answer is:
engender
'create' is the definition.
(I know that engender is a more specific form of the action cause)
'purpose in green movement?' is the wordplay.
'purpose' becomes 'end' (I've seen this in another clue).
'in' indicates putting letters inside.
'movement?' indicates an anagram (I've seen 'movement' mean this (letters move around)).
'green' is an anagram of 'enger'.
'end' going within 'enger' is 'ENGENDER'.
(Other definitions for engender that I've seen before include "Give rise to, cause" , "Father" , "Bring forth" , "Precipitate" , "Give rise to; beget" .)