An abnormal condition of a human, animal or plant that causes discomfort or dysfunction; distinct from injury insofar as the latter is usually instantaneously acquired.
(by extension) Any abnormal or harmful condition, as of society, people's attitudes, way of living etc.
Lack of ease; uneasiness; trouble; vexation; disquiet.
To cause unease; to annoy, irritate.
To infect with a disease.