spook

 
Pronunciation: /spuːk/
informal

noun

  • 1a ghost.
  • 2chiefly North American a spy: a CIA spook
  • 3 offensive, dated, chiefly US a black person.

verb

[with object]
  • frighten; unnerve: they spooked a couple of grizzly bears
  • [no object] (especially of an animal) take fright suddenly: he’ll spook if we make any noise

Origin:

early 19th century: from Dutch, of unknown origin