Sombrous means dark and gloomy, like when the sky is full of clouds and the sun is hidden.
When something is sombrous, it can make people feel sad or thoughtful.
Examples:
The sombrous clouds covered the sky.
The old house looked sombrous in the fading light.
She felt sombrous on the rainy day.
The sombrous room made him want to go outside.
The sombrous forest was full of mystery and shadows.
The sombrous music made her think of sad things.