The quality of being spooky or scary.
Spookinesses can be fun at Halloween, but they can also be frightening.
Examples:
The old house has a lot of spookinesses.
I don't like the spookinesses in that movie.
She feels the spookinesses in the dark forest.
The spookinesses of the haunted house make me shiver.
The spookinesses of the abandoned graveyard are enough to give anyone chills.
The spookinesses of the ghost story stayed with me all night.