Like a ghost (8)
I believe the answer is:
spectral
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">like a ghost</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for spectral that I've seen before include "Like a colourful band" , "Ghastly" , "Of or like a ghost" , "Rap Celts for being ghostly" , "Spooky" .)