Glum means sad and quiet, like a gray cloud has settled over your mood. When you're feeling glum, you're sort of mopey and downcast, without much energy or enthusiasm for anything.

You might feel glum after your team loses an important game, or when a friend moves away, or on a rainy Sunday afternoon when there's nothing fun to do. Someone who's glum often shows it in their face and body: slumped shoulders, a frown, staring at the floor. If your usually cheerful friend seems glum at lunch, you might ask what's wrong.

The word suggests a mood that sticks around for a while, not just a quick moment of frustration. You might be briefly annoyed when you lose at checkers, but you'd feel glum if you studied hard for a test and still did poorly. Being glum is heavier than being a little sad, but lighter than being truly miserable.