Trim wood (6)
I believe the answer is:
spruce
I believe this is a double definition.
'trim' is the first definition.
(synonyms)
'wood' is the second definition.
(spruce is a kind of wood)
(Other definitions for spruce that I've seen before include "Neat and trim like fir tree" , "Well-groomed - tree" , "Neat - evergreen" , "tree with needle-like leaves" , "Elegant" .)