The compound adjective 'well-greased' is a transparent combination of two English elements. The adverb 'well,' with its Old English root meaning "abundantly" or "properly," intensifies the participle 'greased,' which derives from the Latin term for fat, crassus. Literally describing a mechanism thoroughly lubricated with fat or oil to minimize resistance, the term's logic is a direct metaphor. This concrete image of seamless physical operation was naturally extended to describe any system, process, or social interaction that functions with exceptionally smooth and effortless efficiency.

Structure: well (thoroughly) + greased (coated with grease) - well: From Old English wel, meaning "in a good way, satisfactorily, thoroughly." It functions as an intensifying adverb in this compound. - greased: From the verb grease, itself from Old French graisse, gresse (fat), from Latin crassia (fat). The -ed suffix forms the past participle, here used adjectivally to mean "coated with grease."