Pale mauve colour (5)
I believe the answer is:
lilac
'pale mauve colour' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for lilac that I've seen before include "Pale mauve colour for a flower" , "Shade" , "Shrub with fragment purple or white flowers" , "Flowering tree of the olive family" , "Shrub (but not always this colour)" .)