[noun] changing to a darker color Synonyms:blackening
[adjective] becoming dark or darker as from waning light or clouding over; "the darkening sky"
[adjective] characterized by hopelessness; filled with gloom; "gloomy at the thought of what he had to face"; "gloomy predictions"; "a gloomy silence"; "took a grim view of the economy"; "the darkening mood" Synonyms:gloomy, grim