المعنى الاصطلاحي :

All what goes against the Qur’an, the Sunnah, or the consensus of the early Muslim generations ("salaf") of beliefs and forms of worship which people have invented in the religion based on their personal desires and opinions.

الشرح المختصر :

"Muhdathāt al-umoor" (invented matters) includes all beliefs or actions that are introduced into the religion that conflict with the way of the Prophet, may Allah"s peace and blessings be upon him, and his Companions. It can also refer to anything that has no origin in the religion. Any action whereby a slave seeks to draw close to Allah, the Exalted, and that has no evidence from the Qur’an or the Sunnah is a religious innovation. The more the slave seeks to draw close to Allah by way of such an action, the more distant he becomes. Innovations fall under two categories: 1. Belief-related innovations: This is when a slave believes in something that goes against the truth with which Allah, the Exalted, sent His Messenger, may Allah"s peace and blessings be upon him, and revealed in His Book. An example of this is what the "Jahmiyyah" introduced into the religion by their negation of Allah"s beautiful names and sublime attributes, as well as other innovations related to matters of belief, such as claiming that the Qur’an is created and that Allah, the Exalted, will not be seen on the Day of Judgment. 2. Worship-related innovations: It is when a slave worships Allah through newly invented actions and situations that Allah does not permit and whereof He accepts nothing. This is like celebrating the night of the middle of Sha‘bān; celebrating the birthday of the Prophet, may Allah"s peace and blessings be upon him; and other newly invented matters.