Sanguine: Hopeful, confident, cheerful; having an optimistic outlook.  

Sanguine comes from the Latin word sanguineus, meaning blood red.  

Doctors once thought patients with excess blood were more cheerful, hopeful, and confident.  

But, sanguine can also mean several other things.  

Sanguine means reddish, rosy or flushed.   For example: After a rather public faux pas, his complexion remained sanguine for several minutes.  

Sanguine also means blood-red.  For example, The interior of the British warships ships at Trafalgar was painted a sanguine color to obscure the horrors of combat.  

Synonyms of sanguine include: hopeful, optimistic, and upbeat