It is not permissible for a woman to wear men’s clothing, and it is not permissible for a man to wear women’s clothing. A stern prohibition, accompanied by a curse, was narrated concerning that, which indicates that it is a major sin. It was narrated that Ibn `Abbas (may Allah be pleased with him) said: The Messenger of Allah (blessings and peace of Allah be upon him) cursed men who imitate women and women who imitate men. Narrated by al-Bukhari, 5885.
And it was narrated from Abu Hurayrah that the Prophet (blessings and peace of Allah be upon him) cursed men who wear women’s clothing and women who wear men’s clothing. Narrated by Abu Dawud, 4098; classed as authentic (sahih) by al-Albani in Sahih Sunan Abi Dawud.
This prohibition applies to that which is specific to each gender, according to people’s customs.
As for that which is not specific to either gender, as it may be worn by both, and anyone who sees it will not immediately think that this is clothing for the opposite gender, it is not subject to the prohibition, and this is to be decided based on the customs and traditions of a society.
Shaykh as-Sa`di (may Allah have mercy on him0 said regarding men and women resembling one another:
Things are of three types:
Those which are common to both men and women, whether different types of clothing or other things. These things are permissible for both genders, because the basic principle is that things are permissible, and there is no issue of one gender imitating the other in this case.
Those which are specifically for men, so they are not permissible for women.
Those which are specifically for women, so they are not permissible for men.
End quote from Bahjat Qulub al-Abrar, p. 145.
Shaykh Ibn `Uthaymin (may Allah have mercy on him) said: Clothing may be divided into three categories: that which is only for men and that which is only for women – and people do not differ concerning that – and that which is common to both. As for the first and second, the matter is clear, meaning that a man should not wear women’s clothing and a woman should not wear men’s clothing.
As for the third category, there is nothing wrong with something being common to both agendas, like some shirts that are worn by men and women equally.
End quote from Fat-h Dhil-Jalali wal-Ikram bi Sharh Bulugh al-Maram, 5/367.
Shaykh `Abd al-Muhsin al-`Abbad (may Allah preserve him) was asked:
In some countries, there is women’s clothing that is similar to men’s clothing; it resembles it closely and there is no difference between them except that the women wear hijab.
He replied: If this is the case, and this is what really happens, then the resemblance of the opposite gender may occur in a different way, meaning that in the case of clothing, if a certain colour is only worn by men or is only worn by women, and that is known to be the custom, then no man should wear any colour that is traditionally known to be only for women or is well-known to be only for women, and vice versa.
End quote from Sharh Sunan Abi Daud, by al-`Abbad, 13/460.
Shaykh `Abd al-Karim al-Khudayr (may Allah preserve him) said: With regard to clothing in which one cannot tell whether it is for men or for women, then in this case something should be added to it to differentiate between men and women. But there are some types of light clothing which, if you see someone wearing them, you cannot tell whether this is a man or a woman! Such matters are something that may be tolerated. End quote.
From the statements and comments of the scholars quoted above, it will become clear that defining what clothing is for each gender is a matter that is to be referred to sound customs and traditions.
So if the T-shirt mentioned is not something that is traditionally regarded as being only for men, it is not prohibited for you to wear it. And if it so happens that the woman cannot wear it outside the house because it is adornment, or it shows the `awrah when she puts it on, then this is another reservation about it, but it does not prevent her from wearing it at home.
But if it is a kind of clothing that is only for men, then it is not permissible for a woman to wear it.
And Allah knows best.