a state of partial or total darkness
"he struck a match to dispel the gloom"
a feeling of melancholy apprehension
"A deep sense of gloom settled over the crowd as they realized their hopes for peace were fading."
Darkness, dimness, or obscurity.
"The sudden power outage plunged the room into an unsettling gloom where we could barely see our hands."
To be dark or gloomy.
"The sudden clouds cast a heavy gloom over the playground, making everyone pause their game to watch the rain start falling."