The Collaborative International Dictionary of English v.0.48:

Sanguine \San"guine\, a. [F. sanguin, L. sanguineus, fr. sanguis
   blood. Cf. Sanguineous.]
   1. Having the color of blood; red.
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            Of his complexion he was sanguine.    --Chaucer.
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            Like to that sanguine flower inscribed with woe.
                                                  --Milton.
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   2. Characterized by abundance and active circulation of
      blood; as, a sanguine bodily temperament.
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   3. Warm; ardent; as, a sanguine temper.
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   4. Anticipating the best; cheerfully optimistic; not
      desponding; confident; full of hope; as, sanguine of
      success; a sanguine disposition.
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   Syn: Warm; ardent; lively; confident; hopeful; optimistic.
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The Collaborative International Dictionary of English v.0.48:

Sanguine \San"guine\, n.
   1. Blood color; red. --Spenser.
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   2. Anything of a blood-red color, as cloth. [Obs.]
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            In sanguine and in pes he clad was all. --Chaucer.
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   3. (Min.) Bloodstone.
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   4. Red crayon. See the Note under Crayon, 1.
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The Collaborative International Dictionary of English v.0.48:

Sanguine \San"guine\, v. t.
   To stain with blood; to impart the color of blood to; to
   ensanguine.
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WordNet (r) 3.0 (2006):

sanguine
    adj 1: confidently optimistic and cheerful
    2: inclined to a healthy reddish color often associated with
       outdoor life; "a ruddy complexion"; "Santa's rubicund
       cheeks"; "a fresh and sanguine complexion" [syn: rubicund,
       ruddy, florid, sanguine]
    n 1: a blood-red color

Moby Thesaurus II by Grady Ward, 1.0:

124 Moby Thesaurus words for "sanguine":
   agape, agog, all agog, ambivert, anticipant, anticipating,
   anticipative, anticipatory, aspiring, assured, awaiting, beaming,
   blithe, blithesome, blood-colored, bloodstained, bloodthirsty,
   bloody, bloody-red, blooming, blowzed, blowzy, bright,
   bright and sunny, burnt, certain, cheerful, cheery, choleric,
   confident, cycloid, cyclothyme, cyclothymic, eager, ectomorph,
   elated, endomorph, ensanguined, enthusiastic, eupeptic, euphoric,
   exalted, exhilarated, expectant, expecting, extrovert, fervid,
   florid, flush, flushed, fond, forearmed, forestalling, forewarned,
   forward-looking, full of hope, full-blooded, gaping, genial, glad,
   gladsome, glowing, gory, happy, hectic, high, homicidal, hopeful,
   hoping, in anticipation, in expectation, in good heart,
   in good spirits, in high spirits, in hopes, introvert,
   irrepressible, laughing, looking for, looking forward to,
   melancholic, mesomorph, murdering, not surprised, of good cheer,
   of good hope, optimistic, phlegmatic, pleasant, prepared, radiant,
   ready, red-complexioned, red-faced, red-fleshed, riant, rosy,
   rosy-cheeked, rubicund, ruddy, ruddy-complexioned, ruddy-faced,
   sanguinary, sanguineous, schizoid, schizothyme, secure,
   self-assured, self-confident, smiling, sparkling, sunburned, sunny,
   sure, syntone, undespairing, undoubtful, unsurprised, upbeat,
   waiting, waiting for, watching for, winsome, zealous