complaintcom·plaint /kəmˈpleɪnt/ noun1[countableC, uncountableU] a written or spoken statement by someone complaining about somethingOur sales assistants are trained to deal with customer complaints in a friendly manner.
a letter of complaint
complaint aboutThousands of customers have made complaints about the bank’s Internet banking service.
2[countableC]LAW a statement made by a person bringing a case or making a claim in a court of law, stating the facts upon which the case or claim is based 3[countableC]LAW a statement made by one person against another in a legal case, either in a court or to an officer of the courtThe defence counsel pointed out that the complaint had not been served until 14 February this year.