Skinny jeans are stretchy jeans, i.e mostly cotton with some polyester and elastene. Jeggings are usually polyester and spandex... leggings made to look like skinny jeans. I love skinny jeans, would not be caught dead in jeggings. Perhaps because I don't have an issue wearing skinny jeans aside from the fact that the ones I can get my massive feet through the legs of will not cling like leggings from my knees and up.