'deficiently' originates from Latin, specifically the word 'deficere,' where 'de-' meant 'away' and 'facere' meant 'to do or make.'

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

Initially, it meant 'lacking or failing,' but over time it evolved into its current meaning of 'in a manner that lacks something essential or necessary.'