Definitions

1. adjective

causing or feeling a feeling of fear, horror, or unease; frightening or intimidating

“The abandoned mansion is considered the spookiest place in town.”

2. superlative of spook

the most frightening or intimidating

“This haunted house is the spookiest I have ever seen.”

3. noun

a person or thing that is frightening or intimidating

“The spookiest part of the movie was the monster in the dark corner.”