'watt-hungry' originates from modern English composition of the unit name 'watt' and the adjective 'hungry' to form a compound meaning 'hungry for watts' (i.e., consuming many watts). 'Watt' itself is named after the 18th-century engineer 'James Watt', used as the SI unit of power; 'hungry' comes from Old English 'hungor' meaning 'hunger'.

'watt' was coined as the name of the unit in the 19th century to honor James Watt; 'hungry' derives from Old English 'hungor'. The compound 'watt-hungry' is a recent informal technical coinage (late 20th to early 21st century) modeled on compounds like 'power-hungry' and 'energy-hungry'.

Initially the components separately meant 'the unit of power named after James Watt' and 'feeling hunger'; combined, the phrase originally conveyed a playful image of being 'hungry for watts' and has come to mean 'consuming a lot of electrical power' in technical and informal contexts.