Thicket, a small wood (5)
I believe the answer is:
copse
This clue is a double definition.
'thicket' is the first definition.
('copse' can be a synonym of 'thicket')
'a small wood' is the second definition.
(I've seen this before)
(Other definitions for copse that I've seen before include "Cluster of trees" , "Harvested woodland" , "Small thicket" , "Stand of trees" , "Cultivated woodland area" .)