Gyaru (literally Gal) is a Japanese fashion that focuses on girly glamor. Teased (usually blond) wigs, circle lenses, fake nails, fake eyelashes, and fake tans are all considered major defining features within the Gyaru style. Generally Gyaru is often described as "Japanese youth's interpretation of sterotypical California fashion". It's generally seen as a rebellious fashion in Japan because it disregards the traditional ideas of Japanese beauty.
There are many different sub-styles of Gyaru that range from the cute to sexy to grotesque that come and go in popularity, but many of them do not intersect with Lolita with the exception of Himegyaru.