'data-deficient' originates from the combination of 'data,' derived from Latin 'datum,' meaning 'something given,' and 'deficient,' from Latin 'deficere,' meaning 'to fail or lack.'

'data' evolved from the Latin 'datum' through Middle English, while 'deficient' transformed from Latin 'deficere' through Old French 'deficient' and eventually became the modern English word 'deficient.'

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