Immunocompromised refers to a condition in which an individual's immune system is weakened or impaired, making them more susceptible to infections and diseases. This can be due to various factors, such as certain medical treatments (e.g., chemotherapy, organ transplantation), underlying health conditions (e.g., HIV/AIDS, autoimmune disorders), or genetic disorders. People who are immunocompromised have a reduced ability to fight off infections and may require special precautions and medical interventions to protect their health.