Ghost, spectre (7)
I believe the answer is:
phantom
I believe this is a double definition.
'ghost' is the first definition.
(I know that ghost can be written as phantom)
'spectre' is the second definition.
(I've seen this before)
(Other definitions for phantom that I've seen before include "Wraith" , "Blush" , "Spirit" , "RR" , "Apparition, spectre" .)