Syringa (5)
I believe the answer is:
lilac
'syringa' is the definition.
(I know that syringa can be written as lilac)
This is all the clue.
(Other definitions for lilac that I've seen before include "garden ornamental" , "Pinkish purple - shrub" , "Tree with purple or white flowers" , "Flowering tree of the olive family" , "Shade" .)