Short answer
Leaving the home without need, wearing adornment or getting engaged during iddah is a sin, so she should repent and keep the rest of the iddah. The iddah does not restart and has no kaffarah; it still ends on its normal date. A nikah contracted during iddah is not valid and the couple must separate.
Staying in the marital home and avoiding adornment (hidad) are wajib on a widow for the whole iddah. Breaking them is sinful and needs tawbah, but the iddah is counted by time and ends on schedule regardless. A marriage contracted during iddah is invalid (fasid), and they must separate; if it was consummated, she owes a new iddah from the separation.
The four schools agree on this.
Explanation
Many widows worry that they have "broken" their iddah by going out once, wearing a little perfume, or attending a family event. The word "break" makes it sound like the iddah is ruined and must start again. It is not. The iddah is a set time, four months and ten days or until birth, and it ends when that time ends.
If she did something not allowed, such as going out for leisure, spending a night away from home without need, wearing makeup or jewellery, or accepting a direct proposal:
- It was a sin, small or larger depending on what it was. She should regret it, ask Allah's forgiveness and resolve to keep the rest properly.
- The iddah carries on and ends on its date. It does not restart, and there is no fine or kaffarah.
- If she did it because she did not know the rules, or was pressured by family, Allah is forgiving. Learn the rules and carry on calmly.
Things that do not break iddah. Going out by day for real need (work, hospital, the bank), speaking on the phone, seeing visitors, praying and reading Quran are all allowed. See what a widow can do during iddah.
Marriage during iddah. This is the serious case. Allah says: do not resolve on the marriage contract until the prescribed term has run its course. A nikah during iddah is not valid. The couple must separate at once, and a new nikah can be done after the iddah ends. Because the details matter here, ask a mufti. To check the end date, use the iddah calculator.
Ask a mufti about your own case. This answer explains the general ruling. When the details of your situation matter, as they do here, ask a qualified mufti and give them the full facts. Where to ask a scholar.
The evidence
Quran, Surah Al-Baqara 2:234
وَٱلَّذِينَ يُتَوَفَّوْنَ مِنكُمْ وَيَذَرُونَ أَزْوَٰجًۭا يَتَرَبَّصْنَ بِأَنفُسِهِنَّ أَرْبَعَةَ أَشْهُرٍۢ وَعَشْرًۭا ۖ فَإِذَا بَلَغْنَ أَجَلَهُنَّ فَلَا جُنَاحَ عَلَيْكُمْ فِيمَا فَعَلْنَ فِىٓ أَنفُسِهِنَّ بِٱلْمَعْرُوفِ ۗ وَٱللَّهُ بِمَا تَعْمَلُونَ خَبِيرٌۭ ﴿٢٣٤﴾
And those who are taken in death among you and leave wives behind - they, [the wives, shall] wait four months and ten [days]. And when they have fulfilled their term, then there is no blame upon you for what they do with themselves in an acceptable manner. And Allah is [fully] Acquainted with what you do.
The widow's iddah is a set length of time.
Quran, Surah Al-Baqara 2:235
وَلَا جُنَاحَ عَلَيْكُمْ فِيمَا عَرَّضْتُم بِهِۦ مِنْ خِطْبَةِ ٱلنِّسَآءِ أَوْ أَكْنَنتُمْ فِىٓ أَنفُسِكُمْ ۚ عَلِمَ ٱللَّهُ أَنَّكُمْ سَتَذْكُرُونَهُنَّ وَلَٰكِن لَّا تُوَاعِدُوهُنَّ سِرًّا إِلَّآ أَن تَقُولُوا۟ قَوْلًۭا مَّعْرُوفًۭا ۚ وَلَا تَعْزِمُوا۟ عُقْدَةَ ٱلنِّكَاحِ حَتَّىٰ يَبْلُغَ ٱلْكِتَٰبُ أَجَلَهُۥ ۚ وَٱعْلَمُوٓا۟ أَنَّ ٱللَّهَ يَعْلَمُ مَا فِىٓ أَنفُسِكُمْ فَٱحْذَرُوهُ ۚ وَٱعْلَمُوٓا۟ أَنَّ ٱللَّهَ غَفُورٌ حَلِيمٌۭ ﴿٢٣٥﴾
There is no blame upon you for that to which you [indirectly] allude concerning a proposal to women or for what you conceal within yourselves. Allah knows that you will have them in mind. But do not promise them secretly except for saying a proper saying. And do not determine to undertake a marriage contract until the decreed period reaches its end. And know that Allah knows what is within yourselves, so beware of Him. And know that Allah is Forgiving and Forbearing.
Marriage during iddah is forbidden.
Sunan Abi Dawud 2300
Graded sahih... امكثي في بيتك حتى يبلغ الكتاب أجله ...
"Stay in your house until the prescribed term is complete."
Staying in the home is part of the widow's iddah.
Where the ruling is recorded
- al-Hidaya, Kitab al-Talaq, Bab al-'Iddah and the section on hidad. The widow's duties during iddah; the iddah ends with its time.
- Radd al-Muhtar (Ibn Abidin), Kitab al-Talaq, Bab al-'Iddah. Marriage during iddah is fasid and requires separation.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.