Ghostliness, scariness (8)
I believe the answer is:
eeriness
This clue is a double definition.
'ghostliness' is the first definition.
(synonyms)
'scariness' is the second definition.
(thesaurus)
(Other definitions for eeriness that I've seen before include "Weird quality" , "'Weirdness, scariness (8)'" , "Ghostly atmosphere" , "Strange and frightening quality" , "Is serene (anag.)" .)