In islam hijab (modest dress) is interpreted

Great question, I'm a Muslim and wear hijab as well. Muslims are commanded by Allah (God) in The Quran to protect themselves by dressing modestly

"Say to the believing men that: they should cast down their glances and guard their private parts (by being chaste). This is better for them." Quran 24:30

" ... and not display their beauty except what is apparent, and they should place their khumur over their bosoms ... "

So basically Muslim women cover their beauty to those that aren't close.