1.  spook(n = noun.person) creep, weirdie, weirdo, weirdy - someone unpleasantly strange or eccentric;
is a kind of disagreeable person, unpleasant person

2.  spook(n = noun.cognition) ghost, shade, specter, spectre, wraith - a mental representation of some haunting experience; "he looked like he had seen a ghost"; "it aroused specters from his past"
is a kind of apparition, fantasm, phantasm, phantasma, phantom, shadow
Derived form verb spook₁

   spook(v = verb.emotion) - frighten or scare, and often provoke into a violent action; "The noise spooked the horse"
is one way to affright, fright, frighten, scare
Derived form noun spook₂
Sample sentences: The performance is likely to spook Sue

1.  A spirit; a ghost; an apparition; a hobgoblin. Ld. Lytton. [1913 Webster]

2.  The chimæra. [1913 Webster]

spook, n. & v.
--n.
1 colloq. a ghost.
2 US sl. a spy.
--v. US sl.
1 tr. frighten, unnerve, alarm.
2 intr. take fright, become alarmed.

Etymology:
Du., = MLG spok, of unkn. orig.

N  demon, daemon, demonry, demonology, evil genius, fiend, familiar, daeva, devil, bad spirit, unclean spirit, cacodemon, incubus, Eblis, shaitan, succubus, succuba, Frankenstein's monster, Titan, Shedim, Mephistopheles, Asmodeus, Moloch, Belial, Ahriman, fury, harpy, Friar Rush, vampire, ghoul, afreet, barghest, Loki, ogre, ogress, gnome, gin, jinn, imp, deev, lamia, bogie, bogeyman, bogle, nis, kobold, flibbertigibbet, fairy, brownie, pixy, elf, dwarf, urchin, Puck, Robin Goodfellow, leprechaun, Cluricaune, troll, dwerger, sprite, ouphe, bad fairy, nix, nixie, pigwidgeon, will-o'-the wisp, ghost, revenant, specter, apparition, spirit, shade, shadow, vision, hobglobin, goblin, orc, wraith, spook, boggart, banshee, loup-garou, lemures, evil eye, merman, mermaid, merfolk, siren, satyr, faun, manito, manitou, manitu, possession, demonic possession, diabolic possession, insanity, Maxwell's demon, demoniac, demonic, demonical, impish, demoniacal, fiendish, fiend-like, supernatural, weird, uncanny, unearthly, spectral, ghostly, ghost-like, elfin, elvin, elfish, elflike, haunted, pokerish, possessed, possessed by a devil, possessed by a demon, demonically.