gloomy (adj.)
1580s, probably from gloom (n.) even though that word is not attested as early as this one. Shakespeare used it of woods, Marlowe of persons. Gloomy Gus has been used in a general sense of "sullen person" since 1902, the name of a pessimistic and defeatist newspaper comics character introduced about that time by U.S. illustrator Frederick Burr Opper. Related: Gloomily; gloominess.