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 is His slave and Messenger.
First of all, it is permissible for a woman to wear short trousers at home with the following conditions:
1- There should be no imitation of men by doing so. If there is imitation of men, it becomes forbidden as it is confirmed that the Prophet cursed the women who imitate men as reported by Al-Bukhari .
2- There should be no imitation of dissolute or non-Muslim women by doing so; if there is an element of imitating them, it is not permissible for her to wear it as it is confirmed that the Prophet said: ''Whoever imitates a people he is one of them.” [Abu Daawood]
3- She should not appear with the trousers in front of non-Mahram (marriageable) men even if they are long trousers. This is because trousers shape the body and so there is a kind of unveiling one’s body and this is not permissible except when in front of the husband alone. Besides, she is permitted to wear short trousers in front of women provided she does not disclose her ‘Awrah (parts of the body that must be covered) in front of them. The ‘Awrah is between the navel and the knee. However, it is better for a woman not to unveil in front of other women except that which usually appears when she is doing housework, like the face, the head and the hands to the elbows and the like.
As regards wearing short trousers in front of Mahrams (non-marriageable men) then if the trousers are short to an extent that they are above the knee, then it is not permissible for her to wear them in front of them. However, if the trousers do not show more than the leg [they are not above the knee] and are loose and do not outline the shape of the body, then the ruling here depends on the ruling on a woman showing a woman showing her leg in front of the Mahrams.
The view of the majority of the scholars from among the Hanafi, Shaafi’i and Hanbali Schools is that a man is permitted to look at the leg of his female Mahram when he is secure from temptation. Nonetheless, the Maaliki School of jurisprudence says, “The leg of a woman is an ‘Awrah even in regard to male Mahrams."
In any case, a woman should not unveil her leg in front of her male Mahrams, especially in this day and age where evil and temptation are widespread.
This is also because some scholars are of the view that it is absolutely forbidden for a woman to wear trousers even if they are long and even if this is in front of the husband only. This is because in principle, trousers are worn by men only; if a woman wears them, she commits the prohibition of imitating men. As women have taken to wearing them commonly, some scholars issued a Fatwa that it is forbidden for women to wear trousers, as a way of preventing and closing the doors of evil and temptation.
Allaah Knows best.