ill

Ill is a term used to describe a state of poor health or ailment. As an adjective, it commonly refers to feeling sick or unwell, as in "I'm feeling ill," and it can also describe non-physical conditions such as ill humor or ill fortune. As a noun, the form "ill" is rare in everyday speech; more typical nouns are illness or sickness, which refer to the condition of being unwell at a given time or over a longer period.

Etymology and usage of the word reflect a historical breadth. The term has roots in Old English and has carried both bodily and moral connotations in various periods. In some languages and contexts, related words link illness with misfortune or wrongdoing, an association that has diminished but is still visible in some phrases and idioms.

Medical distinctions commonly used in health contexts separate illness from disease and other medical conditions. Illness generally denotes the lived experience of symptoms and impairment, while disease refers to a recognized medical diagnosis supported by signs, tests, or pathology. Conditions can be acute or chronic. Common illnesses include colds, influenza, and infections; chronic illnesses include diabetes, heart disease, and arthritis.

Impact and response: Illness can affect work, school, and social life, leading individuals to seek evaluation and care. Management typically involves identifying the underlying cause and pursuing appropriate treatment, which may include rest, fluids, medications, therapy, or lifestyle adjustments. Public health efforts aim to prevent spread of infectious illnesses and mitigate risk factors for chronic conditions.

See also: health, disease, illness, medical condition, wellness.