The closest thing it would translate to is bikini model, but even that is not totally accurate. I've gotten a bunch of different definitions from different people, but the main thing they seem to agree on is the gravure idols are attractive young women who do a lot of bikini modelling, as well as semi-nude pictures, but never actually show anything scandelous. Kinda like big teases if you ask me. However, in an increasing crowded niche industry, a lot of newer idols (like Kawase Yuna or Aoki Rin before she became just another AV idol) are pushing things more and more into the area of softcore porn to get noticed, although IMHO these are usually your B-grade idols who need a little something extra to get noticed.
By : http://www.gijo.org