Unearthly flying carpet's left (8)
I believe the answer is:
spectral
'unearthly' is the definition.
(thesaurus)
'flying carpet's left' is the wordplay.
'flying' indicates an anagram (letters fly around into new positions).
'left' becomes 'l' (common abbreviation).
'carpets' with letters rearranged gives 'spectra'.
'spectra'+'l'='SPECTRAL'
(Other definitions for spectral that I've seen before include "covering a range of colours" , "Ghostly; of bands of colour" , "Rap Celts for being ghostly" , "Spooky" , "Like a colourful band" .)