'deficient' originates from Latin, specifically the word 'deficiens,' where 'de-' meant 'down from' and 'facere' meant 'to do or make.'

'deficiens' transformed into the Old French word 'deficient,' and eventually became the modern English word 'deficient' through Middle English.

Initially, it meant 'lacking or failing,' and this meaning has largely remained the same in modern usage.