The term "customer complaints" refers to any expression of dissatisfaction or discontent by a customer regarding a product, service, or experience. In other words, it is when a person who has purchased something or availed a particular service feels that they have not received what they expected and therefore complain about the same. These complaints can range from minor issues to major problems, but all of them are important as they provide businesses with valuable feedback on how to improve their offerings and meet customer expectations better.