Spectre, phantom (6)
I believe the answer is:
spirit
This clue is a double definition.
'spectre' is the first definition.
(I've seen this before)
'phantom' is the second definition.
(thesaurus)
(Other definitions for spirit that I've seen before include "essence" , "Courage, energy" , "Distilled alcoholic drink" , "Short" , "The sort of drink" .)