Question
What is the ruling on wearing a lower garment that fits exactly the waist of a man in the state of Ihraam? May Allah reward you.
Answer
All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His Slave and Messenger.
The Prophet pointed out the clothes that are prohibited for men to wear while in the state of Ihraam. It was narrated in Al-Bukhari and Muslim and other books on the authority of ‘Abdullaah ibn ‘Umar, may Allah be pleased with him, that a man asked the Prophet "O Messenger of Allah, what kind of clothes should the one in the state of Ihraam wear?” The Prophet said: “He should not wear a shirt, a turban, trousers, a headcloak or leather socks, unless he can find no slippers, he may then wear leather socks after cutting off what might cover the ankles. He should not wear clothes which are scented with saffron or Waras."
Shaykh Ibn ‘Uthaymeen commented on this Hadeeth in his Fatwas (rulings) saying, "The Prophet pointed out the clothes that should not be worn despite the fact that he was asked about what should be worn. This means that everything can be worn except what was mentioned by the Prophet .”
Hence, the abovementioned types of clothing that are worn by people in general are prohibited for men who are assuming the state of Ihraam and any other thing is lawful. Therefore, wearing a lower garment that fits exactly the waist, if this is not the trousers that are prohibited in the abovementioned Hadeeth, is lawful.
And Allah knows best.