what are cankles? Cankles is a term used to describe when one's ankles swell and become puffy. It is usually caused by fluid retention in the feet or legs, which causes an increase in pressure on the joints and ligaments. The term cankles was coined in 2004 by Dr. Howard Sobel, a podiatrist from New York City. They are also called "fluffy ankles" or "chubby ankles."