Purple (5)
'purple' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for lilac that I've seen before include "Flower celebrated by Schubert" , "Shrub with fragment purple or white flowers" , "Mauve-like colour" , "Pale violet hue" , "Pinkish purple - shrub" .)
(Other definitions for heart that I've seen before include "bottle" , "Vital part" , "one needs to beat" , "Feeling" , "Muscular organ for blood circulation" .)
(Other definitions for haze that I've seen before include "Fish of salmon family" , "Mistiness" , "Slight atmospheric mist" , "Film" , "Mist or shimmer due to heat" .)
(Other definitions for rain that I've seen before include "See 12" , "Weather - shower" , "bad weather" , "The right" , "Falling water" .)