忧郁 (yōu yù): sullen; depressed; melancholy; dejected

Since her best friend moved abroad, she has been very melancholy and often sits alone by the window staring into space.

The ending of this novel is very melancholy: the protagonist loses all his relatives and finally leaves his hometown alone.

After hearing the bad news, his eyes became very gloomy, and he didn't speak all day.

The blue tones in her painting give a melancholy feeling, as if telling a sad story from the past.

It rained for several days in a row, and the weather was gloomy, which made people's mood become melancholy as well.

After losing his job, he has been very depressed, unwilling to go out to see friends or answer the phone.