If you describe something as dark, you mean that it is related to things that are serious or unpleasant, rather than light-hearted. Their dark humor never failed to astound him + darkly dark·ly The atmosphere after Wednesday's debut was as darkly comic as the film itself see also pitch-dark
lacking enlightenment or knowledge or culture; "this benighted country"; "benighted ages of barbarism and superstition"; "the dark ages"; "a dark age in the history of education"
A dark place or area is mysterious and not fully known about. the dark recesses of the mind
marked by difficulty of style or expression; "much that was dark is now quite clear to me"; "those who do not appreciate Kafka's work say his style is obscure"
stemming from evil characteristics or forces; wicked or dishonorable; "black deeds"; "a black lie"; "his black heart has concocted yet another black deed"; "Darth Vader of the dark side"; "a dark purpose"; "dark undercurrents of ethnic hostility"; "the scheme of some sinister intelligence bent on punishing him"-Thomas Hardy
showing a brooding ill humor; "a dark scowl"; "the (Atasözü)ially 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"