'incapable' originates from Middle French, specifically the word 'incapable', where 'in-' meant 'not' and 'capable' meant 'able to do something'.

'incapable' changed from the Middle French word 'incapable' and eventually became the modern English word 'incapable'.

Initially, it meant 'not able to do something', and this meaning has largely remained the same in modern usage.