To mope means to move around slowly and sadly, feeling sorry for yourself and showing everyone how unhappy you are. When someone mopes, they might slouch on the couch with a gloomy face, drag their feet as they walk, or sit alone looking miserable instead of joining in with others.

Picture a kid whose friend can't come over to play. Instead of finding something else fun to do, they mope around the house, sighing dramatically and acting like nothing could possibly cheer them up. That's moping: dwelling on disappointment in a way that spreads the gloom around.

The word suggests a somewhat passive, self-pitying kind of sadness. Someone who mopes isn't crying or actively upset; they're just radiating misery and hoping others will notice.

A person can also be called a mope, though that's less common: “Don't be such a mope!” The past tense is moped: “He moped around all afternoon.”