low-energy

The compound adjective 'low-energy' is a modern formation from two established English words. 'Low' originates from a Germanic root related to lying flat or being close to the ground, evolving to describe anything of small degree or intensity. 'Energy' has a classical pedigree, entering English via Late Latin from the Greek energeia, a philosophical term for "actuality" or "being at work," from ergon ("work"). The literal combination, "low work-capacity," logically yields the contemporary meanings. It first described physical systems with minimal kinetic or potential energy before being applied metaphorically to human behavior characterized by lethargy or lack of enthusiasm, perfectly illustrating how a technical scientific term crosses into everyday descriptive language.

Structure: low (not high) + energy (capacity for activity) low: From Old English hlāw, hlǣw ("mound, hill"), later influenced by Old Norse lágr ("low"). In this compound, it functions as an adjective meaning "small in amount or degree; below the normal level." energy: From Greek energeia ("activity, operation"), from en- ("in, at") + ergon ("work"). In this compound, it functions as a noun meaning "the capacity for vigorous activity; available power."