WordNet (r) 3.0 (2006):

poltergeist
    n 1: a ghost that announces its presence with rapping and the
         creation of disorder

Moby Thesaurus II by Grady Ward, 1.0:

84 Moby Thesaurus words for "poltergeist":
   Dingbelle, Fifinella, Hob, Hobgoblin, Masan, Ouija, Puck,
   apparition, appearance, astral, astral spirit, automatic writing,
   automatism, bad fairy, bad peri, banshee, control, departed spirit,
   deviling, devilkin, diablotin, disembodied spirit, duppy, dybbuk,
   eidolon, elf, erlking, form, ghost, grateful dead, gremlin, guide,
   hant, haunt, idolum, immateriality, imp, incorporeal,
   incorporeal being, incorporeity, kobold, larva, lemures,
   levitation, little devil, manes, materialization, oni, phantasm,
   phantasma, phantom, pixie, planchette, poltergeistism, presence,
   psychography, psychorrhagy, puck, revenant, shade, shadow, shape,
   shrouded spirit, specter, spectral ghost, spirit,
   spirit manifestation, spirit rapping, spook, sprite, table tipping,
   telekinesis, teleportation, telesthesia, theophany, tokoloshe,
   trance speaking, unsubstantiality, vision, walking dead man,
   wandering soul, wraith, young devil, zombie