The Collaborative International Dictionary of English v.0.48:

Unilluminated \Unilluminated\
   See illuminated.

WordNet (r) 3.0 (2006):

unilluminated
    adj 1: without illumination; "came up the lightless stairs";
           "the unilluminated side of Mars"; "through dark unlighted
           (or unlit) streets" [syn: lightless, unilluminated,
           unlighted, unlit]

Moby Thesaurus II by Grady Ward, 1.0:

75 Moby Thesaurus words for "unilluminated":
   awkward, beamless, black, black as night, blankminded, caliginous,
   callow, dark, dark as night, dark as pitch, darkling, darksome,
   dim, dumb, dusk, dusky, ebon, ebony, eclipsed, empty, empty-headed,
   gauche, gloomy, green, groping, ignorant, inane, inexperienced,
   innocent, know-nothing, murky, naive, nescient, night-black,
   night-clad, night-cloaked, night-dark, night-enshrouded,
   night-filled, night-mantled, night-veiled, obfuscated, obscure,
   obscured, occulted, pitch-black, pitch-dark, pitchy, raw, rayless,
   simple, starless, strange to, sunless, tenebrious, tenebrose,
   tenebrous, tentative, unacquainted, unapprized, uncomprehending,
   unconversant, unenlightened, unfamiliar, uninformed, uninitiated,
   unintelligent, unknowing, unlighted, unlit, unposted, unripe,
   unsure, unversed, vacuous