La Roux hair refers to hairstyles modeled after that of Elly Jackson, lead singer for the British synthpop band La Roux. Jackson's hair is red and teased and molded into a vertical wave shape that stands straight up from her scalp. As of 2010, her look had been copied by many girls in London and has also shown up on mannequins in clothing store display windows.
Jackson's hairstyle is created by spraying hair with several different types of hairspray before blow drying. After drying, the hair is separated into sections, with the roots sprayed again. By this time, the hair is fairly solid and can be shaped manually. Once the shape is in place, Jackson sprays it again to hold the wavy shape in place.
The band La Roux chose its name, which means "the red-haired one," based in part on Jackson's red hair. In addition, the band's name combines "roux," the masculine form of the word for "red," with the feminine article "la," rather than the masculine article "le" that would normally be required to make a comment on Jackson's tomboyish demeanor. The band broke up in May 2014, leaving Jackson as the sole remaining member of La Roux, according to Wikipedia.