The act of suffocating someone is known as asphyxiation. This is the process of depriving a person of oxygen, which can lead to unconsciousness or death. Asphyxiation can be caused by choking, strangulation, or blocking the airways. It can also be caused by exposure to hazardous gases, such as carbon dioxide or carbon monoxide. In some cases, asphyxiation can be intentional, as in the case of murder or suicide. In other cases, it can be accidental, such as when someone is unintentionally exposed to hazardous gases.