What is the ruling on a woman cutting a portion of her aunt’s hair while standing at Arafah, knowing that her aunt is elderly and illiterate, and what must she do?

The scholars have unanimously agreed on prohibiting the pilgrim in a state of ihram (definition) from removing their hair, except for a valid excuse. If your aunt's hair was removed against her will or while she was asleep, then there is no sin or expiation (fidyah (definition)) upon her. This is the view of the Hanbalis, Ishaq, Abu Thawr, Ibn al-Mundhir, and one of the two sayings of Al-Shafi'i. However, if it was removed with her knowledge and permission, then the majority of scholars obligate expiation upon her, whether she was aware of the ruling or ignorant of it, and the expiation is to be sent to the poor of the Haram (definition). The more preponderant view is that there is no expiation upon her if she was ignorant of the ruling, as is the position of Sheikh al-Islam Ibn Taymiyyah and others.