Synonyms: dark, dim, murky, dusky, shady, shadowy
These adjectives indicate the absence of light or clarity. Dark, the most widely applicable, can refer to a lack or near lack of illumination (a dark night), deepness of shade or color (dark brown), somberness (a dark mood), or immorality (a dark past). Dim means having or producing little light (dim shadows; a dim light bulb) and further suggests lack of sharpness or clarity: "the terrible dim faces known in dreams" (Carson McCullers). "tales now dim and half forgotten" (Jane Stevenson).
Murky refers to a thick or clouded darkness: "Dolphins use sonar beams to navigate the murky depths of the ocean" (Tim Hilchey).
Like dim, it is also used of what is indistinct or uncertain: "Modern warfare is murky, and with no clear frontlines, the distinction between combat and support can become meaningless" (Kristin Henderson).
Dusky suggests a subdued half-light: "The dusky night rides down the sky, / And ushers in the morn" (Henry Fielding).
It can also refer to deepness or darkness of color: "A dusky blush rose to her cheek" (Edith Wharton).
Shady refers literally to what is sheltered from light, especially sunlight (a shady grove of pines) or figuratively to what is of questionable honesty (shady business deals). Shadowy also implies obstructed light (an ill-lit, shadowy street) but may refer to what is indistinct or little known: "[He] retreated from the limelight to the shadowy fringe of music history" (Charles Sherman).
It can also refer to something that seems to lack substance and is mysterious or sinister: a shadowy figure in a black cape.