All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The Muslim woman may not go out with pants, neither jeans nor anything else, because this constitutes imitating men, which is forbidden under the Sharee'ah, and because it displays the physical details of the woman and causes temptation. The woman may wear whatever she likes, provided that the following conditions are met:
-She does not wear anything that shows the size of her body parts or her skin.
-She does not dress in a way which involves imitation of men or of immoral or disbelieving women.
-The dress should not be intended for fame or be a form of adornment in itself.
-The dress should not be scented or perfumed.
The Muslim woman should adhere to this Sharee'ah-approved dress code regardless of whether she lives in a Muslim or a non-Muslim country. Indeed, exposing her adornment before disbelievers is even more forbidden than exposing it before Muslims. A sincere Muslim is the one who is proud of his religion and proud of Islam. He is not the one who shows defeatism in applying the rulings of Islam before the disbelievers, moreover, he seeks to influence them rather than get influenced by them.
Allaah Knows best.