My uncle's been home feeling melancholy.
This song can really blow the gloom away.
My depression's bothering me today and I can't get myself to study Japanese.
A gloomy energy has filled the room. This makes for a gloomy feeling. One of melancholy.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own. Careful of the shortening of 鬱 or you'll feel gloomy.