The Collaborative International Dictionary of English v.0.48:

Conscious \Con"scious\, a. [L. conscius; con- + scire to know.
   See Conscience.]
   1. Possessing the faculty of knowing one's own thoughts or
      mental operations.
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            Some are thinking or conscious beings, or have a
            power of thought.                     --I. Watts.
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   2. Possessing knowledge, whether by internal, conscious
      experience or by external observation; cognizant; aware;
      sensible.
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            Her conscious heart imputed suspicion where none
            could have been felt.                 --Hawthorne.
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            The man who breathes most healthilly is least
            conscious of his own breathing.       --De Quincey.
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   3. Made the object of consciousness; known to one's self; as,
      conscious guilt.
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            With conscious terrors vex me round.  --Milton.

   Syn: Aware; apprised; sensible; felt; known.
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WordNet (r) 3.0 (2006):

conscious
    adj 1: intentionally conceived; "a conscious effort to speak
           more slowly"; "a conscious policy" [syn: conscious,
           witting]
    2: knowing and perceiving; having awareness of surroundings and
       sensations and thoughts; "remained conscious during the
       operation"; "conscious of his faults"; "became conscious that
       he was being followed" [ant: unconscious]
    3: (followed by `of') showing realization or recognition of
       something; "few voters seem conscious of the issue's
       importance"; "conscious of having succeeded"; "the careful
       tread of one conscious of his alcoholic load"- Thomas Hardy