A Complaint

1. The act of complaining.
2. A grievance, problem, difficulty, or concern.
3. (law) In a civil action, the first pleading of the plaintiff setting out the facts on which the claim is based;

The purpose is to give notice to the adversary of the nature and basis of the claim asserted.

4. (law) In criminal law, the preliminary charge or accusation made by one person against another to the appropriate court or officer, usually a magistrate.

However, court proceedings, such as a trial, cannot be instituted until an indictment or information has been handed down against the defendant.

5. A bodily disorder or disease; the symptom of such a disorder.

(in criminal law, the preliminary charge or accusation made by one person against another to the appropriate court or officer) criminal complaint, complaint of an offence/offense, (penal) charge, (criminal) charges, criminal information, informing the police/authorities, notification of the police/authorities, reporting an offence/offense to the police/authorities