Like a ghost (8)
I believe the answer is:
spectral
'like a ghost' is the definition.
(I've seen this before)
This is the entire clue.
(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" .)