'unwellness' originates from the prefix 'un-' meaning 'not' and the word 'well,' which means 'in good health.'

'unwellness' evolved from the Old English word 'wel,' meaning 'in a good state,' with the addition of the prefix 'un-' to denote the opposite state.

Initially, it meant 'not in a good state,' and this meaning has largely remained the same in modern usage.