sanguine

sanguine \SANG-gwin\, adjective, noun;
Also used as a noun, red iron-oxide crayon used in making drawings:

1. cheerfully optimistic, hopeful, or confident
2. reddish; ruddy
3. (in old physiology) having blood as the predominating humor and consequently being ruddy-faced, cheerful, etc.
4. blood-red; red
5. Heraldry. a reddish-purple tincture.
6. a red iron-oxide crayon used in making drawings

I had now arrived at my seventeenth year, and had attained my full height, a fraction over six feet. I was well endowed with youthful energy, and was of an extremely sanguine temperament.
-- Henry Bessemer

by 1319, "type of red cloth," from Old French sanguin (feminine form, sanguine), from Latin sanguineus "of blood," also "bloody, bloodthirsty," from sanguis "blood." Meaning "blood-red" is recorded from 1382. Meaning "cheerful, hopeful, confident" first attested 1509, since these qualities were thought in medieval physiology to spring from an excess of blood as one of the four humors.