A more thorough explanation:

Disappearance refers to the act of a person being arrested, detained, or abducted by a government or political organization, and then refusing to acknowledge the arrest or detention, or provide information about the whereabouts of the victim(s). This is considered a crime against humanity and is punishable under the Rome Statute of the International Criminal Court.

The ICC Elements of Crimes defines the crime as follows:

• The perpetrator arrested, detained, or abducted one or more persons;
• The perpetrator later refused to acknowledge the arrest, detention, or abduction and to give information as to the whereabouts of the victim(s);
• The perpetrator knew that the arrest would be followed by such refusal;
• The arrest and subsequent refusal were carried out or authorized by a government or political organization;
• The conduct was committed in part of a widespread or systematic attack against a civilian population, and the perpetrator knew as much.

For example, during the military dictatorship in Argentina from 1976 to 1983, thousands of people were disappeared by the government. They were taken from their homes or workplaces, often in the middle of the night, and never seen again. The government denied any knowledge of their whereabouts and refused to provide information to their families or human rights organizations.

Another example is the ongoing conflict in Syria, where enforced disappearances have been used as a tactic by the government and various armed groups. People are taken from their homes or arrested at checkpoints, and their families are not informed of their whereabouts. Many are believed to have been tortured or killed while in custody.

These examples illustrate how disappearance is a serious violation of human rights and can have devastating effects on individuals and their families.