Pastel shade
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">pastel shade</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for lilac that I've seen before include "Lavender colour" , "Plant" , "Light purple - flowering tree" , "Tree with purple or white flowers" , "Shade" .)