Synonyms for Dark:

adj.

angry, upset (adjective)
sulky, frowning, sullen, scowling, glowering, glum, dour.
black (adjective)
midnight, sable, dingy, charcoal, ebony, black.
dark (adjective)
dreary, dusky, darkened, lightless, inky, gloomy, sooty, murky, silhouetted, somber, dim, swarthy, black, dismal, shady, cloudy, shadowy, umbrageous, obscure, shaded.
darkish (adjective)
dim.
dim (adjective)
misty, lightless, unilluminated.
dirty (adjective)
sooty.
dull (adjective)
hazy, unlit.
evil (adjective)
corrupt, immoral, iniquitous.
evil, satanic (adjective)
corrupt, immoral, wicked.
grim, hopeless (adjective)
sinister, dismal, unpropitious, morose, foreboding, joyless, cheerless.
hidden, secret (adjective)
concealed, cryptic, deep.
ignorant (adjective)
unenlightened, benighted, ignorant, uncultivated.
incomprehensible (adjective)
impenetrable.
invisible (adjective)
covert, imperceptible, invisible, concealed, indiscernible, camouflaged, unapparent, Obscured, hidden, latent, unobservable.
lack of light (adjective)
black, caliginous, nebulous, dingy, murky, cloudy, dusky, vague, dim, pitchy, gloomy, indistinct, somber, crepuscular, unlit, shadowy, dusk, opaque, sunless, unlighted, pitch-dark, clouded, darkened, foggy, faint, misty, sooty, lightless, shady, stygian, blackish, aphotic, shaded, overcast, obscure, cimmerian, inky, dull, tenebrous.
night (adjective)
nighttime, twilight, eventide, evening, night, dusk.
opaque (adjective)
murky, opaque, unclear, cloudy, vague, impenetrable, hazy, obscure.
overcast (adjective)
overcast.
shaded complexion, hair (adjective)
swarthy, brunette, dark-skinned, sable, ebony, brunet, bistered, tan.
sullen (adjective)
broody, contrary, mean, fretful, malevolent, cynical, glowering, ungenial, dour, petulant, grouchy, grumpy, sullen, dejected, noncooperative, sour, gloomy, moody, unfriendly, Moping, obstinate, cross, dissociable, grim, glum, long-faced, surly, irascible, sulky, uncooperative, cantankerous, beetle-browed, scowling, morose, melancholy, crabby, hostile, frowning, unsociable.
tenebrific (adjective)
tenebrific, broody.
ulterior (adjective)
Obscured.
unenlightened (adjective)
benighted.

n.

brooding, clouded, appealing, darkly, curious, bug-eyed, misty, deep, pitchy, light, beatific, nebulous, sunless, bright, indistinct, absent, foggy, overcast, dull, faint. in, opposite, go up, on, rep, method acting, acting, cryptic, secret, dramatic. unpropitious, painful, terrible, unhappy, tragic, heartbreaking, foreboding, upsetting. amber, avocado, beige, alabaster, azure, african, negro, baby blue, amethyst, indian, tan. sordid, amoral, perverted, deviant, gross. uncertain, anonymous, strange, personal, private. fatalistic, negative, colors, broken, despairing, blackish. Black-a-vised, bistered, Flaxen, fair-haired, blond, fair, auburn. happy, color-coded, bold, brash, desolate, chintzy, joyless, ablaze, clean. Lowery, Complexioned, bloodless, bronzed, warn, brown, Complected, albino, color. hope, pessimistic. obscureness, dimness, obscurity, murkiness. dark (noun)
pitch-dark, caliginous, saturnine, dour, incomprehensible, acherontic, tenebrific, darkening, unlit, inactive, wicked, darkness, tenebrious, colored, tenebrous, lightproof, nighttime, glum, obscure, gloomy, moody, grim, glowering, stygian, gloomful, darkened, morose, benighted, black, ill-natured, evil, cheerless, acheronian, night, glooming, twilight, blue, cimmerian, coloured, concealed, iniquity, wickedness, dim, uncomprehensible, dusky, brunette, dark-skinned, sour, twilit, disconsolate, lightless, sullen, crepuscular, uncheerful, darkish, light-tight, unenlightened, brunet, dispiriting, depressing, unilluminated, shadow, darkling, sinister, subdued, aphotic, unlighted, dismal.
darkness (noun)
shadow, dimness, the dark, shade, gloom, murk, blackness.
dismal (noun)
hopeless.
night (noun)
sundown, sunset, vesper.
place, time without light (noun)
evening, obscurity, shade, nighttime, murkiness, gloom, night, twilight, murk, darkness, dimness, midnight.
state (noun)
darkness, wickedness.

Other synonyms:

Acherontic
acherontic.
Flaxen, darkly, opposite, fair-haired, bistered, brooding, beatific, faint, auburn, gloom, Black-a-vised, murkiness, blackish, obscureness, appealing, bug-eyed, dimness, method acting, Lowery. obscurity, acting, dull, curious, dramatic. joyless, absent, rep, desolate. fair, go up, pessimistic. in, on. Stygian
stygian.
cloudy
overcast, sunless.
indistinct
nebulous.
shadowy
pitchy.
Other relevant words:
overcast, blackish, uncertain, darkness, cheerless, darkling, sinister, faint, secret, indistinct, dull, clouded, benighted, darkish.

Usage examples for dark

  1. Why is it so dark in there? – Dr. Adriaan by Louis Couperus
  2. Dark day, isn't it? – The Iron Woman by Margaret Deland
  3. And neither could have gone very far in the dark – The Enchanted Canyon by Honoré Willsie Morrow