The compound adjective "waist-length" is a transparent descriptive formation in Modern English. The first element, "waist," evolved from Old English and Old Norse terms related to bodily size and form, eventually narrowing to specify the part of the torso between the ribs and hips. The second element, "length," originates from the Proto-Germanic root for "long," combined with an abstract noun suffix. The compound logically combines these two native English morphemes to create a precise measurement term, literally meaning "having the extent or measurement down to the waist," primarily used to describe garments or hair.

Structure: waist (body part) + length (measurement) - waist: From Old English wæstm (growth, form, stature), later influenced by Old Norse veistr (size, stature). In this compound, it denotes the part of the body. - length: From Old English lengþu, derived from lang (long) + the noun-forming suffix -þu (-th). In this compound, it denotes the extent or measurement.