A grouch is someone who complains frequently and seems perpetually grumpy or irritable. You know that person who grumbles about everything: the weather's too hot, then too cold, the music's too loud, the room's too quiet? That's a grouch.

The word often describes someone whose bad mood has become their whole personality. While everyone has cranky moments, a grouch stays in that state most of the time. Think of Oscar the Grouch from Sesame Street, who lives in a garbage can and delights in being disagreeable. That's where the show's creators got his name.

You might call your brother a grouch when he wakes up complaining about breakfast, then grumbles through the car ride, then mutters about having to go to school. But sometimes people use it more affectionately, like calling your grandfather a lovable grouch because he pretends to be annoyed by things but you can tell he's not really upset.

The word can also be a verb: to grouch means to complain in that characteristic grumpy way. “Stop grouching about the rain and grab an umbrella!” The related word grouchy describes the mood itself: someone feeling grouchy is irritable and hard to please.