A complaint is an expression of dissatisfaction or unhappiness about something. When you make a complaint, you're saying that something isn't right, isn't fair, or isn't working the way it should.

Complaints come in many forms. You might complain to your teacher that the classroom is too cold, or lodge a complaint with a store manager about a broken toy you just bought. A neighbor might file a complaint with the city about a pothole in the street. In each case, the person complaining wants someone to know about a problem and, usually, to fix it.

Some complaints are serious and important: they alert people to real problems that need solving. Other complaints are minor grumbles that don't accomplish much. If you complain constantly about small things (the cafeteria food, the weather, having to wait five minutes), people may stop listening when you have a legitimate concern.

In legal settings, a complaint is a formal document that begins a lawsuit, laying out what someone believes another party did wrong. But in everyday life, a complaint is simply how we communicate when something falls short of what we expected or deserve.