The Collaborative International Dictionary of English v.0.48:

Voodooism \Voo"doo*ism\, n. [Probably (through Creole French
   vaudoux a negro sorcerer) fr. F. Vaudois Waldensian, because
   the Waldenses were accused of sorcery.]
   A degraded form of superstition and sorcery, said to include
   human sacrifices and cannibalism in some of its rites. It is
   prevalent among the negroes of Haiti, and to some extent in
   the United States, and is regarded as a relic of African
   barbarism.
   [1913 Webster]

WordNet (r) 3.0 (2006):

voodooism
    n 1: a religious cult practiced chiefly in Caribbean countries
         (especially Haiti); involves witchcraft and animistic
         deities [syn: voodoo, vodoun, voodooism, hoodooism]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "voodooism":
   alchemy, bewitchery, charm, divination, enchantment, fetishism,
   glamour, gramarye, hoodoo, juju, jujuism, magic, natural magic,
   necromancy, obeah, rune, shamanism, sorcery, sortilege, spell,
   spellbinding, spellcasting, sympathetic magic, thaumaturgia,
   thaumaturgics, thaumaturgism, thaumaturgy, theurgy, vampirism,
   voodoo, wanga, white magic, witchcraft, witchery, witchwork,
   wizardry