Main entry: lowering, heavy, sullen, threatening
Definition: darkened by clouds
Usage: a heavy sky
Main entry: dark, dour, glowering, glum, saturnine, sour, sullen, moody, morose
Definition: showing a brooding ill humor
Usage: a dark scowl; the proverbially dour New England Puritan; a glum, hopeless shrug; he sat in moody silence; a morose and unsociable manner; a saturnine, almost misanthropic young genius- Bruce Bliven; a sour temper; a sullen crowd