What actions someone might take that would make his fasting officially void? In other words ... some 'Mufties' said that not praying during fasting doesn't nullify the fasting. But of course it is Haraam and his fasting might be considered incomplete. I want to know what else than eating and drinking during fasting causes fasting to be void.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

We have already clarified the difference of opinion among the scholars whether a person who abandons the prayer out of laziness is a non-Muslim and goes out of the fold of Islam, or is only a dissolute person but not a non-Muslim. The validity or invalidity of fasting of a person who abandons the prayer is based on this difference of opinion. The scholars who are of the view that whoever abandons the prayer out of laziness does not go out of the fold of Islam, are of the view that his fasting is acceptable and valid. However, the scholars who are of the view that whoever abandons the prayer out of laziness goes out of the fold of Islam, are of the view that his actions are void and are not accepted, and they are of the opinion that fasting and other acts of worship will not benefit him because of him abandoning the prayer. For more details, please refer to Fatwa 85264. We have also clarified the nullifiers of fasting in Fatwa 86709, so please refer to it.

Allaah Knows best.