Lose colour (6)
(Other definitions for whiten that I've seen before include "Blanch" , "free from guilt" , "Become less colourful" , "New hit (anag.)" , "Bleach" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">lose colour</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for fade that I've seen before include "Discolour" , "Gradually grow faint" , "Lose brightness" , "Grow paler" , "Grow dull" .)