Macilency is a rare medical condition that is characterized by extreme thinness and emaciation. The term comes from the Latin word macilentus, which means lean or thin. There are several synonyms for macilency, including cachexia, wasting, frailty, gauntness, and skeletal appearance. People with macilency often exhibit a loss of muscle mass and body fat, as well as weakness and fatigue. The condition can be caused by a variety of factors, including cancer, chronic infections, and eating disorders. Treatment typically involves addressing the underlying cause, as well as providing nutritional support and physical therapy to improve strength and mobility.