from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Impenetrable by light; neither transparent nor translucent.
  • adj. Not reflecting light; having no luster: an opaque finish.
  • adj. Impenetrable by a form of radiant energy other than visible light: a chemical solution opaque to x-rays.
  • adj. So obscure as to be unintelligible: "opaque, elusive, minimal meanings” ( John Simon).
  • adj. Obtuse of mind; dense. See Synonyms at dark.
  • n. Something that is opaque, especially an opaque pigment used to darken parts of a photographic print or negative.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Neither reflecting nor emitting light.
  • adj. Allowing little light to pass through, not translucent or transparent.
  • adj. Unclear, unintelligible, hard to get or explain the meaning of
  • adj. Obtuse, stupid.
  • adj. Describes a type for which higher-level callers have no knowledge of data values or their representations; all operations are carried out by the type's defined abstract operators.
  • n. An area of darkness; a place or region with no light.
  • n. Something which is opaque rather than translucent.
  • v. To make, render (more) opaque.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Impervious to the rays of light; not transparent.
  • adj. Obscure; not clear; unintelligible.
  • n. That which is opaque; opacity.

from The Century Dictionary and Cyclopedia

  • Shady; dark; hence, obscure.
  • Impervious to the rays of light; not transparent.
  • In entomology, having no luster: said of surfaces or colors.
  • In botany, mostly used in the sense of ‘not shining,’ or ‘dull.’
  • A similar ware made at Spode, introduced in 1805. Also called feldspar porcelain and ironstone china.
  • n. Opacity.
  • To render opaque.
  • n. Something opaque; specifically, a shade which can be worn over the forehead to protect the eyes from brilliant light.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. not clearly understood or expressed
  • adj. not transmitting or reflecting light or radiant energy; impenetrable to sight


from The American Heritage® Dictionary of the English Language, 4th Edition

Middle English opake, shady, and French opaque, opaque (from Old French, shady), both from Latin opācus.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English opake, from Latin opacus ("shaded, shady, dark") (of unknown origin), later reinforced from Middle French opaque.


  • And now my chains are to be broken; I shall mount above these clouds and opaque airs in which I live, —opaque, though they seem transparent, —and from the heaven of truth I shall see and comprehend my relations.

    X. Essays. The Poet. 1844

  • That was the agreed signal, a word opaque enough to confuse anyone trying to listen in.

    The Edge of Madness

  • Pensions & Investment Research Consultants Ltd., or Pirc, recommends voting against the remuneration report, because of what it calls "opaque" disclosure and "overly complex" structure of executives' packages.

    Barclays CEO Faces Pay Backlash

  • Paul vowed in an interview with The Hill last month that as chairman he would shine a light on the Fed's policies, which he called opaque and destructive.


  • They have told us that our atmosphere is what they call opaque, so that the stars are not visible, and then they were surprised that we know stars, that we know their music and the movements of their dance far better than beings like you who spend hours studying them through what you call telescopes.

    A Wrinkle in Time

  • The value of such a discovery was obvious from the first; and was still further enhanced by the discovery made shortly that, photographic plates are affected by the rays, thus making it possible to make permanent photographic records of pictures through what we know as opaque substances.

    A History of Science: in Five Volumes. Volume III: Modern development of the physical sciences

  • To get there, Artprice limited its scope to fine-art sales at public auctions, filtering out results from what they refer to as the "opaque" gallery market. News

  • Peter Schroeder at The Hill: Paul vowed in an interview with The Hill last month that as chairman he would shine a light on the Fed's policies, which he called opaque and destructive.

    Yahoo! News: Business - Opinion

  • The reception, to the rear of the ground floor hall space, is all white with one purple wall to create a slightly softer and more welcoming space than the daringly dark remainder of the scheme, with white desking and a giant mirror on the chimney breast; a contemporary take on a baroque frame in opaque acrylic.

    Manchester Square Interior by SHH

  • Keeping prices opaque is one way medical institutions seek to avoid competition and thereby keep prices up.

    How American Health Care Killed My Father


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  • adjective: not clearly understood or expressed

    The meaning of the professor's new research was opaque to most people, so no one asked any questions.

    October 19, 2016

  • Caring for your baby and young child author steven p. shelov and Tanya Remer Altmann page5

    November 2, 2010

  • Jesus is an image of God so utterly transparent as to remain opaque except to the eyes of faith.(online dictionary)

    September 23, 2010

  • "The book is constructed of sequentially numbered sheets of paper (recyclable), each capable of holding thousands of bits of information. The pages are locked together with a custom-fit device called a binder which keeps the sheets in their correct sequence. Opaque Paper Technology (OPT) allows manufacturers to use both sides of the sheet, doubling the information density and cutting costs. Experts are divided on the prospects for further increases in information density."

    - The Book.

    November 1, 2009