Definition: The term "antimasker" is a medical term that refers to a device designed to prevent or reduce the spread of infectious agents, such as viruses and bacteria. These devices typically contain a filter or other device that captures and removes particles from the air or water they come into contact with, thus reducing the risk of infection. The presence of an antimasker is often indicated by its use in healthcare settings, particularly hospitals, to prevent the spread of infectious diseases like COVID-19.