Wiriness is a term used to describe the quality of being lean and muscular. It is often used to describe athletes or people who are physically fit. The term is derived from the word 'SINEW, ' which is a type of connective tissue found in the body that helps to support and strengthen muscles. SINEW is made up of collagen fibers, which are responsible for providing strength and flexibility to the body. Wiriness is a desirable trait for athletes and those looking to stay physically fit, as it helps to improve performance and reduce the risk of injury.