'energy-deficient' originates from the combination of 'energy' and 'deficient', where 'energy' comes from the Greek word 'energeia' meaning 'activity' and 'deficient' from Latin 'deficere' meaning 'to fail or lack'.

'Energy-deficient' combines the modern English words 'energy' and 'deficient', which have been used in English since the 16th and 17th centuries respectively.

Initially, 'deficient' meant 'failing or lacking', and when combined with 'energy', it evolved to mean 'lacking sufficient energy'.