Is it permissible for a wife to take money from her husband secretly and give it in charity without his knowledge, knowing that he trusts her and allows her to dispose of his money for good without informing him of the specific uses?

It is permissible for a woman to give charity from her husband's money if he explicitly permits her or if his consent is customarily known. However, if he forbids her, she is not allowed to do so. Some scholars have opined that it is permissible for her to give a small amount in charity without permission, based on prophetic narrations such as the hadith (definition) of Aisha: "Whatever a woman spends from her husband's house, without causing damage, she will have her reward, and he will have a similar reward for what he earned, and she will have a reward for what she spent, and the treasurer will have a similar reward, without any decrease in their rewards," and the hadith of Asma: "Spend as much as you can afford." The preponderant view is that she is permitted to dispose of a small amount, because it is customary to overlook such small expenditures. However, if the husband forbids her, she is not allowed to give charity from his money. It is stated in the hadith of Abu Umamah: "A woman should not spend anything from her house except with the permission of her husband," and permission was interpreted as explicit permission or inferred from the situation. The Permanent Committee for Scholarly Research and Ifta has issued a fatwa (definition) permitting giving a small, customary amount in charity without explicit permission, as long as it does not harm the husband.