Bidʿah mufassiqah is a belief or practice that entails sinfulness and deviation.
Its examples include:
• Giving a matter religious status on one’s own authority.
• Lowering the standing of a religious matter.
This definition includes practice as well as belief.
1. Fisq: departure from religious obedience into disobedience.
2. Religious matter: a religious ruling or a matter with religious standing.