'energy-wasting' originates from English, formed by the compound of 'energy' and 'wasting'; 'energy' ultimately from French 'énergie' < Greek 'energeia' meaning 'activity, operation', and 'wasting' from Anglo-French 'waster' < Latin 'vastare' meaning 'to lay waste, to squander'.

'energy' entered English via French from Greek 'energeia' and stabilized in Modern English; 'waste' developed from Anglo-French 'waster' (from Latin 'vastare'), with the English present participle 'wasting' used attributively. These elements combined in Modern English to form the hyphenated compound 'energy-wasting'.

Initially, the roots meant 'activity/operation' (for 'energy') and 'to lay waste/squander' (for 'waste'); combined, the modern compound narrowed to the specific idea of 'causing unnecessary consumption of energy'.