gloom·y / ˈgloōmē/ • adj. (gloom·i·er, gloom·i·est) dark or poorly lit, esp. so as to appear depressing or frightening: a gloomy corridor. ∎ feeling distressed or pessimistic: I am by no means gloomy about the prospects for domestic industry. ∎ causing distress or depression: a gloomy atmosphere.DERIVATIVES: gloom·i·ly / -məlē/ adv.gloom·i·ness n.