Praise be... to Allaah.
Our advice is that women should not wear trousers because this is the dress of kaafir women, so they should not wear them. A woman should only wear women’s clothes, the dress of her own country; she should not deviate from that. She should strive to wear concealing and modest clothes which are not tight or see-through, but which cover her and do not show the shape of the body, and which do not resemble the clothes of the kuffaar or of men, or a dress of fame and vanity.
Majmoo’ Fataawa wa Maqaalaat Mutanawwi’ah li Samaahat al-Shaykh al-‘Allaamah ‘Abd al-‘Azeez ibn ‘Abd-Allaah ibn Baaz (may Allaah have mercy on him), vol. 9, p. 43