The Collaborative International Dictionary of English v.0.48:

Obscure \Ob*scure"\, v. t. [imp. & p. p. Obscured
   ([o^]b*sk[=u]rd"); p. pr. & vb. n. Obscuring.] [L.
   obscurare, fr. obscurus: cf. OF. obscurer. See Obscure, a.]
   To render obscure; to darken; to make dim; to keep in the
   dark; to hide; to make less visible, intelligible, legible,
   glorious, beautiful, or illustrious.
   [1913 Webster]

         They are all couched in a pit hard by Herne's oak, with
         obscured lights.                         --Shak.
   [1913 Webster]

         Why, 't is an office of discovery, love,
         And I should be obscured.                --Shak.
   [1913 Webster]

         There is scarce any duty which has been so obscured by
         the writings of learned men as this.     --Wake.
   [1913 Webster]

         And seest not sin obscures thy godlike frame? --Dryden.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

148 Moby Thesaurus words for "obscured":
   abstruse, armored, beamless, beclouded, bedazzled,
   between the lines, beyond one, black, black as night, blind,
   blindfold, blindfolded, buried, caliginous, cased, ceiled, cloaked,
   close, clouded, coated, complex, complicated, concealed, coped,
   covered, covert, cowled, crabbed, cramp, cryptic, curtained, dark,
   dark as night, dark as pitch, darkened, darkling, darksome, dazed,
   dazzled, delitescent, difficult, dormant, ebon, ebony, eclipsed,
   encapsulated, encapsuled, encased, enveloped, enwrapped, esoteric,
   excecate, filmed, floored, garbled, guarded, hard,
   hard to understand, hibernating, hid, hidden, hooded, hoodwinked,
   housed, in a cloud, in a fog, in eclipse, in purdah, in the wings,
   incommunicado, intricate, jumbled, knotty, latent, loricate,
   loricated, lurking, mantled, masked, muffled, mysterious, mystic,
   night-black, night-clad, night-cloaked, night-dark,
   night-enshrouded, night-filled, night-mantled, night-veiled,
   obfuscated, obscure, occult, occulted, overtechnical, packaged,
   paved, perplexed, pitch-black, pitch-dark, pitchy, possible,
   potential, privy, rayless, recondite, roofed-in, scrambled,
   screened, scummed, secluded, secluse, secret, sequestered,
   sheathed, shelled, shielded, shrouded, sleeping, snow-blind,
   snow-blinded, starless, submerged, sunless, swathed, tenebrious,
   tenebrose, tenebrous, tented, tough, under an eclipse, under cover,
   under house arrest, under the surface, under wraps, underground,
   underlying, unilluminated, unknown, unlighted, unlit, unmanifested,
   veiled, virtual, walled, walled-in, wrapped, wrapped in clouds