Eerie apparition (6)
I believe the answer is:
wraith
'eerie apparition' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for wraith that I've seen before include "Ghostly apparition" , "Ghost, spectral apparition" , "Making an emotional appeal" , "Wrath I directed at spirit" , "Ghostly figure" .)