What is the definition of a Nasibi, what is their legal ruling, and what are the sources that have discussed Nasb?

The Nawasib are those who bear enmity towards the Family of the Prophet, peace and blessings be upon him, especially Ali ibn Abi Talib, may Allah be pleased with him. They insult them, or declare them to be immoral (fasiq), or declare them to be disbelievers (kafir). Among the most famous of them are the Khawarij, who rebelled against Ali and declared him a disbeliever. Hatred of the Prophet's Family is a grave innovation. As for declaring the Nawasib to be disbelievers, it depends on the motive. If their hatred is for a worldly reason, they are not declared disbelievers. But if it is for a religious reason, due to their hatred of them for being companions of the Prophet, peace and blessings be upon him, then this is disbelief. The Khawarij are a subject of dispute among scholars regarding their disbelief, but the Ummah is in agreement about condemning them and declaring them astray. The Rawafid frequently accuse the Ahlus-Sunnah of being Nawasib in order to alienate people from them, whereas the Ahlus-Sunnah befriend all believers and disassociate themselves from both the Rawafid and the Nawasib.