The Collaborative International Dictionary of English v.0.48:

Obscure \Ob*scure"\ ([o^]b*sk[=u]r"), a. [Compar. Obscurer
   ([o^]b*sk[=u]r"[~e]r); superl. Obscurest.] [L. obscurus,
   orig., covered; ob- (see Ob-) + a root probably meaning, to
   cover; cf. L. scutum shield, Skr. sku to cover: cf. F.
   obscur. Cf. Sky.]
   [1913 Webster]
   1. Covered over, shaded, or darkened; destitute of light;
      imperfectly illuminated; dusky; dim.
      [1913 Webster]

            His lamp shall be put out in obscure darkness.
                                                  --Prov. xx.
                                                  20.
      [1913 Webster]

   2. Of or pertaining to darkness or night; inconspicuous to
      the sight; indistinctly seen; hidden; retired; remote from
      observation; unnoticed.
      [1913 Webster]

            The obscure bird
            Clamored the livelong night.          --Shak.
      [1913 Webster]

            The obscure corners of the earth.     --Sir J.
                                                  Davies.
      [1913 Webster]

   3. Not noticeable; humble; mean. "O base and obscure vulgar."
      --Shak. "An obscure person." --Atterbury.
      [1913 Webster]

   4. Not easily understood; not clear or legible; abstruse or
      incomprehensible; as, an obscure passage or inscription.
      [1913 Webster]

   5. Not clear, full, or distinct; clouded; imperfect; as, an
      obscure view of remote objects.
      [1913 Webster]

   Obscure rays (Opt.), those rays which are not luminous or
      visible, and which in the spectrum are beyond the limits
      of the visible portion.
      [1913 Webster]

   Syn: Dark; dim; darksome; dusky; shadowy; misty; abstruse;
        intricate; difficult; mysterious; retired; unnoticed;
        unknown; humble; mean; indistinct.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Obscure \Ob*scure"\ ([o^]b*sk[=u]r"), v. i.
   To conceal one's self; to hide; to keep dark. [Obs.]
   [1913 Webster]

         How! There's bad news.
         I must obscure, and hear it.             --Beau. & Fl.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Obscure \Ob*scure"\, n.
   Obscurity. [Obs.] --Milton.
   [1913 Webster]

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]

WordNet (r) 3.0 (2006):

obscure
    adj 1: not clearly understood or expressed; "an obscure turn of
           phrase"; "an impulse to go off and fight certain obscure
           battles of his own spirit"-Anatole Broyard; "their
           descriptions of human behavior become vague, dull, and
           unclear"- P.A.Sorokin; "vague...forms of speech...have so
           long passed for mysteries of science"- John Locke [syn:
           obscure, vague]
    2: marked by difficulty of style or expression; "much that was
       dark is now quite clear to me"; "those who do not appreciate
       Kafka's work say his style is obscure" [syn: dark,
       obscure]
    3: difficult to find; "hidden valleys"; "a hidden cave"; "an
       obscure retreat" [syn: hidden, obscure]
    4: not famous or acclaimed; "an obscure family"; "unsung heroes
       of the war" [syn: obscure, unknown, unsung]
    5: not drawing attention; "an unnoticeable cigarette burn on the
       carpet"; "an obscure flaw" [syn: obscure, unnoticeable]
    6: remote and separate physically or socially; "existed over the
       centuries as a world apart"; "preserved because they
       inhabited a place apart"- W.H.Hudson; "tiny isolated villages
       remote from centers of civilization"; "an obscure village"
       [syn: apart(p), isolated, obscure]
    v 1: make less visible or unclear; "The stars are obscured by
         the clouds"; "the big elm tree obscures our view of the
         valley" [syn: obscure, befog, becloud, obnubilate,
         haze over, fog, cloud, mist]
    2: make unclear, indistinct, or blurred; "Her remarks confused
       the debate"; "Their words obnubilate their intentions" [syn:
       confuse, blur, obscure, obnubilate]
    3: make obscure or unclear; "The distinction was obscured" [syn:
       obscure, bedim, overcloud]
    4: reduce a vowel to a neutral one, such as a schwa
    5: make undecipherable or imperceptible by obscuring or
       concealing; "a hidden message"; "a veiled threat" [syn:
       obscure, blot out, obliterate, veil, hide]

Moby Thesaurus II by Grady Ward, 1.0:

420 Moby Thesaurus words for "obscure":
   Cimmerian, abstruse, adiaphanous, adumbrate, aleatoric, aleatory,
   ambiguous, amorphic, amorphous, amphibological, anarchic,
   anonymous, apply to, arcane, around the bush, back of beyond,
   baffling, baggy, bandage, beamless, beat about, becloud, beclouded,
   bedarken, bedazzle, bedim, befog, befogged, beg the question,
   begloom, belie, bemist, benight, beyond one, bicker, black,
   black as night, black out, blacken, blanket, blear, bleared,
   bleary, blind, blind the eyes, blindfold, blobby, block,
   block the light, blot out, blur, blurred, blurry, boggle, broad,
   brown, buried, caliginous, camouflage, canopy, cast a shadow,
   cavil, chance, chancy, chaotic, characterless, choplogic,
   clabber up, clear as mud, cloak, close, clothe, cloud, cloud over,
   cloud up, clouded, cloudy, complex, complicate, complicated,
   conceal, concealed, confuse, confused, confusing, cope, corrupt,
   cover, cover up, covered, covert, cowl, crabbed, cramp, cryptic,
   curtain, dark, dark as night, dark as pitch, darken, darken over,
   darkling, darksome, daze, dazzle, deform, deprive of sight,
   devious, difficult, dim, dim out, disguise, dismal, disorder,
   disordered, disorderly, dissemble, distant, distort,
   distract attention from, dodge, double-edged, double-faced,
   doubtful, dubious, dull, dusk, dusky, ebon, ebony, eclipse,
   eclipsed, encloud, encompass with shadow, enigmatic, enmist,
   ensconce, enshroud, envelop, equivocal, equivocate, esoteric,
   evade, evade the issue, excecate, faint, falsify, far, far-off,
   featureless, feeble, fence, film, filmy, fog, fog up, foggy,
   foreign, formless, fuliginous, fuzz, fuzzy, garble, garbled,
   general, glare, gloom, gloomy, gloss over, gouge, grumly,
   half-seen, half-visible, hard, hard to understand, haze, hazy,
   hedge, hid, hidden, hide, hit-or-miss, hood, hoodwink, humble,
   ignotus, ill-defined, illegible, impervious to light, imprecise,
   in a cloud, in a fog, in eclipse, in purdah, in the wings,
   inaccessible, inaccurate, inchoate, incoherent, incommunicado,
   incomprehensible, inconclusive, inconsequential, inconspicuous,
   indecisive, indefinable, indefinite, indeterminable, indeterminate,
   indistinct, indistinguishable, inexact, inexplicable, inform,
   inglorious, inscrutable, insignificant, intransparent, intricate,
   jumble, jumbled, kaleidoscopic, keep from, keep under cover,
   knotty, latent, lax, lay on, lay over, little known, lonesome,
   loose, low-profile, lowly, lumpen, make blind, make uncertain,
   make unintelligible, mantle, mask, mean, merely glimpsed, mess up,
   minor, misadvise, misdirect, miseducate, misguide, misinform,
   misinstruct, mislead, misrepresent, mist, misteach, misty, muddle,
   muddy, muffle, murk, murky, mysterious, mystic, mystical, mystify,
   mystifying, nameless, nebulous, night-black, night-clad,
   night-cloaked, night-dark, night-enshrouded, night-filled,
   night-mantled, night-veiled, nitpick, no credit to, nondescript,
   nonspecific, nubilate, nubilous, obduce, obfuscate, obfuscated,
   obnubilate, obscured, obumbrate, occult, occultate, occulted, odd,
   opaque, orderless, out of focus, out-of-the-way, overcast,
   overcloud, overlay, overshadow, oversmoke, overspread,
   overtechnical, pale, palter, parry, perplexed, perplexing, pervert,
   pick nits, pitch-black, pitch-dark, pitchy, prevaricate, pussyfoot,
   put on, puzzling, quibble, random, rayless, recondite, remote,
   removed, renownless, retired, roiled, roily, scramble, scrambled,
   screen, scum, secluded, secluse, secret, semivisible, sequestered,
   shade, shadow, shadowed forth, shadowy, shady, shapeless, shield,
   shift, shroud, shuffle, shy, sidestep, slur over, smog, smoke,
   snow-blind, solitary, somber, split hairs, spread over, starless,
   stochastic, strange, strike blind, subfusc, sunless, superimpose,
   superpose, sweeping, tenebrious, tenebrose, tenebrous,
   tergiversate, tough, transcendent, turbid, umbral, uncelebrated,
   uncertain, unclear, undefined, under an eclipse, under cover,
   under house arrest, under wraps, underground, undestined,
   undetermined, undistinguished, unemphatic, unfamed, unfamiliar,
   unfathomable, unform, unglorified, unheard-of, unhonored,
   unilluminated, unimportant, unintelligible, unknown, unlighted,
   unlit, unnamed, unnotable, unnoted, unnoticeable, unnoticed,
   unordered, unorganized, unplain, unpopular, unrecognizable,
   unremarked, unrenowned, unshape, unspecified, unsung, vague,
   varnish, veil, veiled, weak, whitewash, wrapped in clouds



The Jargon File (version 4.4.7, 29 Dec 2003):

obscure
 adj.

    Used in an exaggeration of its normal meaning, to imply total
    incomprehensibility. ?The reason for that last crash is obscure.? ?The find
    (1) command's syntax is obscure!? The phrase moderately obscure implies
    that something could be figured out but probably isn't worth the trouble.
    The construction obscure in the extreme is the preferred emphatic form.


The Free On-line Dictionary of Computing (30 December 2018):

OBSCURE

   "A Formal Description of the Specification Language OBSCURE",
   J.  Loeckx, TR A85/15, U Saarlandes, Saarbrucken, 1985.

   [Jargon File]