Women whom a man is prohibited (haram) from marrying

According to the Quran and Sunnah, a man cannot marry a particular woman if she is considered haram to him. Most prohibitions are lifelong, while some are temporary. If there are no such restrictions, he can marry any woman.

1. Permanent Prohibitions (Haram for lifetime):  These include close blood relations and certain relationships established through marriage. Quranic verse:
   

   حُرِّمَتْ عَلَيْكُمْ أُمَّهَـٰتُكُمْ وَبَنَاتُكُمْ وَأَخَوَٰتُكُمْ وَعَمَّـٰتُكُمْ وَخَـٰلَـٰتُكُمْ وَبَنَاتُ ٱلْأَخِ وَبَنَاتُ ٱلْأُخْتِ وَأُمَّهَـٰتُكُمُ ٱلَّـٰتِىٓ أَرْضَعْنَكُمْ وَأَخَوَٰتُكُم مِّنَ ٱلرَّضَـٰعَةِ وَأُمَّهَـٰتُ نِسَآئِكُمْ وَرَبَـٰٓئِبُكُمُ ٱلَّـٰتِى فِى حُجُورِكُم مِّن نِّسَآئِكُمُ ٱلَّـٰتِى دَخَلْتُم بِهِنَّ فَإِن لَّمْ تَكُونُوا۟ دَخَلْتُم بِهِنَّ فَلَا جُنَاحَ عَلَيْكُمْ وَحَلَـٰٓئِلُ أَبْنَآئِكُمُ ٱلَّذِينَ مِنْ أَصْلَـٰبِكُمْ وَأَن تَجْمَعُوا۟ بَيْنَ ٱلْأُخْتَيْنِ إِلَّا مَا قَدْ سَلَفَ ۗ إِنَّ ٱللَّهَ كَانَ غَفُورًۭا رَّحِيمًۭا

   You are forbidden to marry your mothers, daughters, sisters, paternal and maternal aunts, as well as the daughters of your brothers and sisters [due to close blood relations]. Additionally, relationships established through breastfeeding also create prohibitions, such as foster-mothers and foster-sisters.

   Also forbidden are relationships established through marriage, such as mothers-in-law, the stepdaughters under your guardianship if you have consummated marriage with their mothers—but if you have not, then you can marry them – nor the wives of your own sons, nor two sisters together at the same time.

   [Quran- 4:23]

2. Temporary Prohibitions (Haram for a term): This typically refers to a woman who is currently married to someone else or a woman who is in her ‘iddah’ (waiting period) after divorce. Additionally, a Muslim cannot marry two sisters at the same time[4:23], nor can they marry non-Muslim women who do not belong to the Ahlul Kitab (People of the Book, i.e., Jews and Christians). Furthermore, a Muslim man who already has four wives cannot marry another woman at the same time.

Conditions and Permissions: If there are no conditions or prohibitions preventing marriage, then a man is generally free to marry a specific woman who is not otherwise forbidden to him.