obscure

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Deficient in light; dark.
• adjective So faintly perceptible as to lack clear delineation; indistinct.
• adjective Indistinctly heard; faint.
• adjective Linguistics Having the reduced, neutral sound represented by schwa (ə).
• adjective Far from centers of human population.
• adjective Out of sight; hidden.
• adjective Not readily noticed or seen; inconspicuous.
• adjective Of undistinguished or humble station or reputation.
• adjective Not clearly understood or expressed; ambiguous or vague: synonym: ambiguous.
• transitive verb To make dim, indistinct, or impossible to see: synonym: block.
• transitive verb To make difficult to discern mentally or understand.
• transitive verb To diminish the stature of; overshadow or detract from.
• transitive verb Linguistics To reduce (a vowel) to the neutral sound represented by schwa (ə).
• noun Something obscure or unknown.

from The Century Dictionary.

• To cover and shut off from view; conceal; hide.
• To darken or make dark; dim.
• To deprive of luster or glory; outshine; eclipse; depreciate; disparage; belittle.
• To render doubtful or unintelligible; render indistinct or difficult of comprehension or explanation; disguise.
• To hide; conceal one's self.
• Dark; deprived of light; hence, murky; gloomy; dismal.
• Living in darkness; pertaining to darkness or night.
• Not capable of being clearly seen, on account of deficient illumination.
• Hence In logic, not clear, as an idea; not sharply distinguished from others.
• Not perspicuous, as a writing or speech; not readily understood, on account of faultiness of expression.
• Hidden; retired; remote from observation: as, an obscure village.
• Unknown to fame; unnoticed; hence, humble; lowly: as, an obscure curate.
• In entomology: Not distinct: as, obscure punctures.
• Not clear; dull or semi-opaque: as, obscure green or red.
• Synonyms Dark, dim, darksome, dusky, rayless, murky.
• 4 and Obscure, Doubtful, Dubious, Ambiguous, Equivocal; difficult, intricate, vague, mysterious, enigmatical. In regard to the meaning of something said or written, obscure is general, being founded upon the figure of light which is insufficient to enable one to see with any clearness; this figure is still felt in all the uses of the word. Doubtful is literal, meaning full of doubt, quite impossible of decision or determination, on account of insufficient knowledge. Dubious may be the same as doubtful, but tends to the special meaning of that doubtfulness which involves anxiety or suspicion: as, dubious battle; dubious prospects; a dubious character. Ambiguous applies to the use of words, intentionally or otherwise, in a way that makes certainty of interpretation impossible; but it may be used in other connections: as, an ambiguous smile. Equivocal applies to that which is ambiguous by deliberate intention. See darkness.
• Unhonored, inglorious.
• noun Obscurity.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb obsolete To conceal one's self; to hide; to keep dark.
• transitive verb 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.
• noun obsolete Obscurity.
• adjective Covered over, shaded, or darkened; destitute of light; imperfectly illuminated; dusky; dim.
• adjective Of or pertaining to darkness or night; inconspicuous to the sight; indistinctly seen; hidden; retired; remote from observation; unnoticed.
• adjective Not noticeable; humble; mean.
• adjective Not easily understood; not clear or legible; abstruse or incomprehensible.
• adjective Not clear, full, or distinct; clouded; imperfect.
• adjective (Opt.) those rays which are not luminous or visible, and which in the spectrum are beyond the limits of the visible portion.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Dark, faint or indistinct.
• adjective Hidden, out of sight or inconspicuous.
• adjective Difficult to understand.
• verb transitive To darken, make faint etc.
• verb transitive To hide, put out of sight etc.

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

• verb make obscure or unclear
• adjective remote and separate physically or socially