Sanguine describes an optimistic, cheerful temperament, or the colour blood red, while sanguinary describes actual bloodshed or a bloodthirsty nature. A sanguine outlook is hopeful; a sanguinary battle is violent.
The core difference
Sanguine relates to a cheerful, confident temperament (or the colour of blood), while sanguinary relates to bloodshed and bloodthirstiness.
- sanguine — cheerfully optimistic and confident, or blood red in colour: despite the setback, she remained sanguine about the project's chances.
- sanguinary — involving bloodshed, or eager to shed blood: the history books describe it as a sanguinary conflict.
How to tell them apart
Both words descend from the Latin sanguis, meaning blood, but they took very different paths. Sanguinary stayed close to the literal sense: it describes violence, bloodshed, or a bloodthirsty temperament. Sanguine drifted further. In old medical theory, a preponderance of blood in the body was thought to produce a cheerful, confident, optimistic temperament, and that association is what survives in the word today.
The trick is to notice the ending: sanguinary, with its extra syllable, is the grim one, tied to bloodshed and violence. Sanguine, shorter and smoother, is the hopeful one, describing someone who stays upbeat even when things look difficult. Because the words look so alike, writers sometimes reach for the wrong one when describing a violent scene or an optimistic outlook.
