Answered by Shaykh Faraz Rabbani
Question: Is it permissible for women to wear trousers or other “fashionable women’s Islamic clothing?”
Answer: In the name of Allah, Most Merciful.
Walaikum assalam wa rahmatullahi wa barakatuh,
In terms of trousers, the short answer is yes, it would be permitted, if they are loose and one’s mid-area is modestly covered.
As for other types of western-style clothing, this returns to the local customs and norms (‘urf). Something highly modest in America may not be modest by the standards of more conservative societies.
Islamic law has placed general guidelines for proper dress:
it must be modest,
loose (especially around sensitive areas–chest and mid-area, for example), and must cover one’s awrah. This is fixed, unalterable guidance.
After this, how it is fulfilled returns to local customs, environment, and one’s situation, and is flexible within the limits of the fixed guidelines of the Qur’an and the luminous guidance of the Beloved of Allah (Allah bless him and give him peace).