Synonyms for Apparitional:

adj.

all (adjective)
ghostly, spiritual, spectral, ghostlike, phantasmal.
ghostly (adjective)
illusory, mythical, demonic, shadowy, supernatural, phantasmal, ghostlike, ghostly, spectral, nightmarish, ghoulish, spiritual.
imaginary (adjective)
chimerical, unreal, unsubstantial.
immaterial (adjective)
impalpable, intangible, ghostly, ethereal.
unsubstantial (adjective)
impalpable, chimerical, insignificance, vacuous, tenuous, inessential, unconcrete, null, intangible, weightless, phantasmal, unreal, nonexistence, vacant, immaterial, unsubstantial, empty, illusory, spectral, ethereal.

n.

apparitional (noun)
ghostly, spiritual, spectral, ghostlike, phantasmal, supernatural.

Other synonyms:

Other relevant words:
ghostlike, spiritual, supernatural.