darkest
dark-est
adjective
Most lacking in light; most obscure, gloomy, or difficult.
"It was the darkest night of the year."
Thesaurus
Synonyms: dark, darkness, glowering, morose, sour, glum, saturnine, dour, sullen, ill-natured, moody, concealed
Antonyms: day, daylight, daytime, light, light-colored, lighting