c.1300 as a verb, "to look sullen or displeased," perhaps from Scandinavian (cf. Norw. dial. glome "to stare somberly"); the noun is 1590s in Scottish, "sullen look," from the verb. Sense of "darkness, obscurity" is first recorded 1629 in Milton's poetry; that of "melancholy" is 1744 (gloomy in this sense is attested from 1580s).