spook

nouns

someone unpleasantly strange or eccentric
creep, spook, weirdie, weirdo, weirdy
a mental representation of some haunting experience
"he looked like he had seen a ghost"; "it aroused specters from his past"
ghost, shade, specter, spectre, spook, wraith

verbs

frighten or scare, and often provoke into a violent action
"The noise spooked the horse"
spook
is a type of (narrower)
cause fear in
"The stranger who hangs around the building frightens me"; "Ghosts could never affright her"
affright, fright, frighten, scare