Illness represents a subjective experience of feeling unwell, often accompanied by suffering or discomfort. It signifies a deviation from an individual’s perceived normal state of health and well-being. Find out about health conditions, including their symptoms and how they're treated. Explore comprehensive guides on hundreds of common and rare diseases and conditions from the experts at Mayo Clinic. A to Z list of common illnesses and conditions including their symptoms, causes and treatments. WebMD Symptom Checker is designed with a body map to help you understand what your medical symptoms could mean, and provide you with the trusted information you need to help make informed decisions. Viral infections are any illness you get from a virus (a small germ that uses your cells to reproduce). Examples include the flu, colds, COVID-19 and HPV. The meaning of ILLNESS is sickness. (Definition of illness from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press) Is there a difference between a disease and an illness? Technically, yes. A disease is something a physician can diagnose, and an illness is something you feel. In humans, disease is often used more broadly to refer to any condition that causes or can cause pain, dysfunction, distress, social problems, or death to the person affected, or similar problems for those in contact with the person.