The compound adjective 'well-draining' is a modern English formation built from native Germanic elements. The core concept, 'drain', originates from the Old English verb drēahnian, related to the act of removing moisture. This was combined with the adverbial 'well', from Old English wel, to indicate the action is performed effectively or satisfactorily. The suffix '-ing' converts the verbal phrase into an adjective, describing a property. Thus, the literal logic of "draining well" directly translates to the modern technical meaning for soil that effectively allows water to percolate away.

Structure: well (satisfactorily) + drain (remove liquid) + ing (adjective-forming suffix) - well: From Old English wel, meaning "in a good way, satisfactorily." It functions as an adverb modifying the participle 'draining'. - drain: From Old English drēahnian, meaning "to strain, filter, remove liquid." It is the core verb root. - ing: A suffix from Old English -ende, -ung, used to form present participles and adjectives from verbs.