sanguine

The story

1. Proto-Indo-European · derived from*h₁sh₂-én-
2. Latin · derived fromsanguineus“of blood”
3. Old French · derived fromsanguin
4. Middle English · inherited fromsanguine
5. English todaysanguine

From Middle English sanguine, from Old French sanguin, ultimately from Latin sanguineus (“of blood”), from sanguis (“blood”) (of uncertain origin, but probably from Proto-Indo-European *h₁sh₂-én-, from *h₁ésh₂r̥ (“blood”), with an obscure suffix such as *-ǵʰ- (related to body parts)) + -inus + -eus. The obsolete medical sense is in reference to the humour (blood) which ancient Hippocratic and later Galenic medicine associated with cheerfulness, optimism, confidence, liveliness, and spiritedness. Doublet of sanguineous.

First known use, by meaning

• from late 14th c. Having the colour of blood; blood red.
• from early 16th c. Anticipating the best; optimistic; confident; full of hope.