Ambiguously or unclearly expressed: enigmatic, esoteric, mysterious, obscure, undefined.
Off the air; not transmitting.
Without moral or spiritual light; sinister, malign.
With emphasis placed on the unpleasant aspects of life; said of a work of fiction, a work of nonfiction presented in narrative form, or a portion of either.
Deprived of sight; blind.
Transmitting, reflecting, or receiving inadequate light to render timely discernment or comprehension: caliginous, darkling, dim, gloomy, lightless, sombre.
Having racing capability not widely known.
Marked by or conducted with secrecy: hidden, secret; clandestine, surreptitious.
Conducive to hopelessness; depressing or bleak.
Lacking progress in science or the arts.
Extinguished.
Dull or deeper in hue; not bright or light.
Having an absolute or (more often) relative lack of light.
Extremely sad, depressing, or somber, typically due to, or marked by, a tragic or undesirable event.
A complete or (more often) partial absence of light.
Ignorance.
Nightfall.
A dark shade or dark passage in a painting, engraving, etc.
To remain in the dark, lurk, lie hidden or concealed.
To make dark, darken; to obscure.
To grow or become dark, darken.
Not explicit, relatively ambiguous.