Opaque

opaque
    adj 1: not transmitting or reflecting light or radiant energy;
           impenetrable to sight; "opaque windows of the jail";
           "opaque to X-rays" [ant: {clear}]
    2: not clearly understood or expressed [syn: {opaque},
       {unintelligible}]
    

Opaque \O*paque"\, a. [F., fr. L. opacus. Cf. {Opacous}.]
   [1913 Webster]
   1. Impervious to the rays of light; not transparent; as, an
      opaque substance.
      [1913 Webster]

   2. Obscure; not clear; unintelligible. [Colloq.]
      [1913 Webster]
    

Opaque \O*paque"\, n.
   That which is opaque; opacity. --Young.
   [1913 Webster]
    

97 Moby Thesaurus words for "opaque":
      Boeotian, abstruse, adiaphanous, ambiguous, amorphous,
      amphibological, arcane, asinine, backward, baffling, becloud,
      beef-brained, beef-witted, black, blind, blockish, blurred, blurry,
      bovine, chumpish, clear as mud, cloddish, cloud, clouded, cloudy,
      cowish, crass, cryptic, dark, darken, dense, dim, doltish, dull,
      dull-witted, dullard, dumb, duncical, duncish, dunderheaded,
      elusive, enigmatic, equivocal, fat, foggy, fuzzy, gross, grumly,
      hazy, impenetrable, impermeable, impervious to light, indefinite,
      indeterminate, indistinct, ineducable, intransparent, klutzy,
      lumpish, misty, muddy, murky, mysterious, mystifying, nebulous,
      nubilous, oafish, obfuscated, obscure, obscured, obtuse,
      perplexing, puzzling, recondite, roiled, roily, shadowy, shapeless,
      slow, smoky, sottish, stolid, stupid, tenebrous, thick,
      thickheaded, transcendent, turbid, uncertain, unclear,
      unfathomable, unintelligent, unintelligible, unplain, unteachable,
      vague, wrongheaded