Scope to changed the thicket (5)
I believe the answer is:
copse
'the thicket' is the definition.
('copse' can be a synonym of 'thicket')
'scope to changed' is the wordplay.
'to changed' indicates an anagram.
'scope' is an anagram of 'COPSE'.
(Other definitions for copse that I've seen before include "spinney" , "Piece of managed woodland" , "Dense growth of shrubs or trees" , "A little wood" , "Small thicket" .)