Definition of dark :
1. A dark shade or dark passage in a painting, engraving, or the like; as, the light and darks are well contrasted.
2. Absence of light; darkness; obscurity; a place where there is little or no light.
3. Deprived of sight; blind.
4. Destitute of knowledge and culture; in moral or intellectual darkness; unrefined; ignorant.
5. Destitute, or partially destitute, of light; not receiving, reflecting, or radiating light; wholly or partially black, or of some deep shade of color; not light- colored; as, a dark room; a dark day; dark cloth; dark paint; a dark complexion.
6. Evincing black or foul traits of character; vile; wicked; atrocious; as, a dark villain; a dark deed.
7. Foreboding evil; gloomy; jealous; suspicious.
8. Not clear to the understanding; not easily seen through; obscure; mysterious; hidden.
9. showing a brooding ill humor; " 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"
10. The condition of ignorance; gloom; secrecy.
11. To darken to obscure.
off-key, gentle, ablaze, naughty, tincture, foreboding, trace, biased, Stygian, darksome, smutty, fair-haired, begrimed, comfortless, hope, unlettered, drear, ghastly, subdued, uneducated, risque, sinfulness, deplorable, complexioned, cheerless, shadower, fuliginous, olive-drab, opprobrious, pitiful, rep, illiterate, minatory, blackish, depressive, slanted, forlorn, dimness, bluish, no-good, on, dreich, unlighted, disastrous, bleached, nighted, albino, dogged, sombre, unforgiving, lonely, black-a-vised, foggy, raunchy, darkness, unrighteous, fatalistic, apart, happy, mordant, uncomprehensible, unlawful, sordid, cimmerian, heavy, solemn, vileness, enigmatic, pitch-black, inactive, inconsolable, wretched, grubby, ominous, sliminess, pertinacious, minacious, miserable, pessimistic, turned, auburn, macabre, aristocratic, bright, wicked, unnoticeable, patrician, nonliterate, contraband, brown, colorful, deviant, ugliness, gray, crepuscular, nefarious, light-tight, sorry, tight-mouthed, baby-blue, secret, desolate, mysterious, warn, occult, bronzed, dire, amoral, menacing, misty, temperamental, colors, fair, Negro, dark-skinned, arcane, ill-natured, phantom, down in the mouth, unsung, African, darkling, unlearned, unrelenting, double-edged, unyielding, blue, iniquity, darkish, distressing, racy, amber, shabbiness, sad, dyed, disgraceful, alabaster, nefariousness, down, personal, villainous, Indian, avocado, unenlightened, chill, apparition, dispiriting, unfairness, caliginous, analphabetic, sinful, obscureness, lowery, bug-eyed, threatening, depressed, rayless, brooding, bleak, no-count, lousiness, immorality, inexorable, muddied, morbid, complected, bad, opposite, depressing, swarthiness, sunless, vicious, lamentable, tenebrious, benighted, untaught, unappeasable, aristocratical, smuggled, incomprehensible, go up, regretful, persistent, relentless, bold, tail, low-spirited, grimy, simple, brash, unsavory, drab, coloured, despairing, profane, wickedness, dull, murkiness, loathsomeness, no-account, closemouthed, Acherontic, isolated, tenebrific, indistinct, close, grungy, beatific, equivocal, light, unethical, cold, ignominious, brunet, reticent, upsetting, glooming, in, beige, uninstructed, gruesome, plutonian, acting, godforsaken, shadow, flaxen, untutored, sinister, clouded, grisly, downcast, blasphemous, gamy, heartbreaking, dramatic, juicy, gloomful, wrong, repulsiveness, off, absent, negative, one-sided, overcast, injustice, broken, gross, amethyst, darkening, unknown, evil, lightproof, low, blue-blooded, Delphic, non-white, gamey, method acting, black-market, chintzy, bloodless, uncommunicative, unconsolable, painful, azure, unlit, ambiguous, tan, darkly, fateful, saturnine, strange, sin, duskiness, brunette, pitch-dark, pitchy, dirty, blackened, phantasma, rude, joyless, shameful, spicy, sick, inglorious, perverted, mystic, swart, vile, tenacious, vestige, private, sepulchral, bootleg, lonesome, stern, tenebrous, appealing, blond, deep, colored, sober, unhappy, puritanical, puritanic, uncertain, anonymous, unilluminated, funereal, cryptic, twilit, elegiac, obscurity, rotten, lowering, unpropitious, baleful, rancid, aphotic, uncheerful, calamitous, color, bistered, terrible, fatal, forbidding, color-coded, tragic, disconsolate, unschooled, inscrutable, good-for-nothing, nebulous, good-for-naught, clean, phantasm, lugubrious, curious, blueish, dimmed, elliptical, unread, downhearted, dispirited, faint, hopeless, acheronian, muddy, meritless, fantasm, false
darkness (part of speech: noun)
invisible (part of speech: adjective)
sullen (part of speech: adjective)
glowering, contrary, fretful, glum, frowning, sullen, scowling, cantankerous, unfriendly, sulky, gloomy, ungenial, surly, obstinate, irascible, crabby, moody, uncooperative, unsociable, beetle-browed, cynical, long-faced, grim, noncooperative, moping, grouchy, hostile, cross, mean, dissociable, dejected, malevolent, sour, petulant, melancholy, broody, grumpy, morose, dour
ignorant (part of speech: adjective)
dark (part of speech: adjective)
black (part of speech: adjective)
opaque (part of speech: adjective)
evil (part of speech: adjective)
night (part of speech: noun)