Praise be to Allah.
A guideline for mourning, for a woman whose husband has died
The guideline on mourning is that the woman who is in mourning should avoid all kinds of adornment for the duration of her ‘iddah following the death of her husband.
Ibn ‘Abd al-Barr (may Allah have mercy on him) said:
With regard to mourning, the woman should refrain from all kinds of adornment in clothing, perfume, jewellery, kohl and whatever else women adorn themselves with, so long as her ‘iddah has not yet ended.
End quote from al-Istidhkaar (18/217-218).
It says in al-Mawsoo‘ah al-Fiqhiyyah al-Kuwaitiyyah (2/107):
The woman who is in mourning should avoid everything that is regarded as adornment either according to Islamic teachings or according to custom, whether it has to do with the body or clothes, or would attract attention to her, such as going out of her house, or showing herself to suitors or accepting proposals from them. This is what that is agreed upon (among the scholars) in general terms. End quote.
The evidence that it is obligatory to avoid adornment includes the hadith of Umm ‘Atiyyah, according to which the Messenger of Allah (blessings and peace of Allah be upon him) said: “No woman should mourn for someone who dies for more than three days, except for a husband, (in which case the period of mourning is) four months and ten days. She should not wear any dyed clothes except clothes dyed with ‘asb (bindweed). She should not apply kohl to her eyes, or use perfume, except for a little qust or azfaar (types of perfume), when she cleans herself after finishing her period. Narrated by al-Bukhaari (5342) and Muslim (938).
And it includes the hadith of Umm Salamah, the wife of the Prophet (blessings and peace of Allah be upon him), [who narrated] from the Prophet (blessings and peace of Allah be upon him) that he said: “The woman whose husband has (recently) died should not wear clothes dyed with safflower or mishq (a reddish clay), or wear jewellery, or dye her hair, or use kohl.” Narrated by Abu Dawood (2304) and an-Nasaa’i (3535); classed as saheeh by Shaykh al-Albaani in Irwa’ al-Ghaleel (7/205).
Ruling on a woman in mourning removing hair from her body:
Based on the above, with regard to a woman removing hair from her body, there are two scenarios:
The first is that which comes under the heading of cleanliness and removing that which causes annoyance. This is not prohibited; rather it is enjoined, such as removing armpit hair.
Ibn Qudaamah (may Allah have mercy on him) said:
She is not prohibited to clean herself by clipping the nails, removing the armpit hair, and shaving the hair that it is recommended to shave, or from washing herself with lotus leaves and combing her hair, because of the hadith of Umm Salamah, and because this is done for the purpose of cleanliness, not for perfuming oneself.
End quote from al-Mughni (11/288).
The second scenario is that which comes under the heading of beautification, such as cutting their hair for the purpose of beautification, or neatening the eyebrows, removing hair from the arms and legs, and so on. This is contrary to what the woman in mourning is instructed to do of avoiding adornment.
Khaleel ibn Ishaaq al-Maaliki (may Allah have mercy on him) said:
She should not use depilatory paste on her body, but there is nothing wrong with removing the pubic hair. This was narrated by al-Lakhmi and Ibn Yoonus from Ashhab…
Maalik said in al-‘Utbiyyah:… There is nothing wrong with looking at [??} a woman, being treated with something, trimming her nails, and plugging her armpit hair.
End quote from at-Tawdeeh (5/66).
Al-Khateeb ash-Sharbeeni (may Allah have mercy on him) said:
Note: based on the above, with regard to mourning, we may state that it is permissible for her to clean herself by washing her hair, trimming her nails, shaving her pubic hair, plucking her armpit hair and removing dirt even if it is visible, because all of this does not come under the heading of beautification which is a call to intimacy. As for the hair removal which is regarded as beautification, such as removing hair around the eyebrows or the top of the forehead, that is not allowed, as was discussed by some scholars, as is quite clear.
With regard to removing hair from the chin or upper lip, it is Sunnah to remove it (for women), as was stated by an-Nawawi in Sharh Muslim.
End quote from al-Iqnaa‘ (3/1197).
And Allah knows best.