Saturnine (SAT-uhr-nyn) Sluggish. Gloomy. Cold. From Latin Saturninus (of Saturn). From the ancient belief in astrology that those born under the planet Saturn’s supposed influence had its characteristics. Since Saturn was the farthest known planet at the time, it was believed to be the slowest and coldest. The planet received its name after the Roman god of agriculture. Earliest documented use: 1433.