means The state or active pursuit of good health, especially as a holistic balance of body and mind rather than the mere absence of illness.

from A straightforward marriage of 'well' (Old English 'wel,' in good health or fortune) and the noun-making suffix '-ness.' The word has existed quietly since at least the 17th century as a plain antonym to 'illness,' but it lay mostly dormant for centuries. Its modern life began in mid-20th-century America, when a physician championed 'wellness' as a positive, whole-person ideal of health — a coinage that the lifestyle and self-care industries would later seize upon and inflate.