'ineffectual' originates from Late Latin, specifically the word 'ineffectualis,' where 'in-' meant 'not' and 'effectualis' meant 'producing an effect.'

'ineffectualis' transformed into the Old French word 'ineffectuel,' and eventually became the modern English word 'ineffectual' through Middle English.

Initially, it meant 'not producing an effect,' and this meaning has largely remained the same in modern usage.