Salam!I was wondering what the ruling on a little bit of the neck or hair showing intentionally is. I don't mean showing the whole neck, just a smaller part of it (if the veil is loose for example or if you wear a turtleneck shirt/dress).I heard of the 'less than a quarter' rule and some scholar's positions as well

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.

It is well-established by the jurists that a woman’s hair is an ‘Awrah, and it is not permissible for her to deliberately reveal any part of it, even if it is only a small part, in the presence of a non-Mahram man.

In his book Kitaab al-Ijmaa’, Ibn Hazm quoted the consensus of the jurists that a woman’s hair is an ‘Awrah. This is in regard to looking at her hair.

As regards the prayer, there is a difference of opinion when a woman uncovers part of her hair, whether or not it invalidates her prayer.

What you referred to as a quarter is included in this, we mean in regard to what is related to the prayer, and not in relation to non-Mahram man looking at it.

The Hanafi School held that the exposure of a quarter of her hair is forgiven, so it does not invalidate the prayer, as in the al-Fatawa al-Hindiyyah (the Indian Fatawa).

The same applies to the woman’s neck; she must cover it, and this is also a matter of consensus among the scholars.

Al-Qurtubi said in his Tafseer: “Muslims are unanimously agreed that the private parts of the man and the woman are an ‘Awrah, and that the entire body of the woman is ‘Awrah with the exception of her face and hands about which they differed in opinion.” [End of quote]

We have not come across any statements of the scholars regarding permitting the woman to show any part of her neck.

For more benefit on a woman not covering her entire hair in prayer, please refer to Fatwa 450679.

Allah knows best.