sinewy

the word "sinewy" is a native english formation, built upon the old english noun "sinew," which referred to a tendon. the old english term itself has germanic roots, likely from a proto-germanic word for "sinew" or "tendon." the suffix "-y," also of old english origin, is added to nouns to create adjectives meaning "characterized by" or "resembling." therefore, the literal construction "full of sinews" directly evolved into its modern meanings. it first described the physical toughness of meat or muscle, then extended metaphorically to describe a lean, muscular physique, and further to characterize anything possessing a similar quality of tough, fibrous strength, such as a piece of writing or a musical performance.

Structure: sinew (tendon) + y (adjective suffix) sinew (from old english seonu, sinu, meaning "tendon, nerve") + y (from old english -ig, an adjective-forming suffix meaning "having the quality of, full of").