a condition of a living animal or plant body, or of a specific part of one, that impairs the performance of a vital function; a sickness or malady
Diseases are the result of something going wrong with the normal everyday functions of the body. They may result from a multitude of causes – such as in-built (or genetic) errors, auto-immune disorders (where the body's own defence mechanisms turn inwards on itself), or damage from without by, for example, viruses, bacteria, toxins or chemicals; they can result in impairment of both mental and physical function and may in some cases be preventable — Dr John Cormack
a harmful or corrupt development, situation, condition, etc
the disease of self-doubt
diseased adj
[Middle English disese uneasiness, sickness, from early French desaise, from dis- + aise: see ease1]