in Islam, any innovation that has no roots in the traditional practice (sunna) of the Muslim community. The most fundamentalist legal school in Islam, the Hanabilah (and its modern survivor, the Wahhabiyah sect of Saudi Arabia) rejected bid'ah completely, arguing that the duty of a Muslim was to follow the example set by the Prophet (sunna) and not try to improve on it. Most Muslims, however, agreed that it was impossible to adapt to changing conditions without introducing some types of innovations. As a safeguard against any excesses, bid'ahs were classified as good (hasan) or praiseworthy (mahmudah), or bad (sayy'ah) or blameworthy (madhmumah). They were further grouped under the five categories of Muslim law as follows: (1) among bid'ahs required of the Muslim community (fard kifayah) are the study of Arabic grammar and philology as tools for the proper understanding of the Qur'an, evaluation of Hadith (traditions or sayings of the Prophet Muhammad) to determine their validity, the refutation of heretics, and the codification of law; (2) strictly forbidden (muharramah) are bid'ahs that undermine the principles of orthodoxy and thus constitute unbelief (kufr); (3) recommended (mandub) is the founding of schools and religious houses; (4) disapproved (makruh) are the ornamentation of mosques and the decoration of the Qur'an; and finally (5) the law is indifferent (mubahah) to the bid'ahs of fine clothing and good food.
BID'AH
Meaning of BID'AH in English
Britannica English vocabulary. Английский словарь Британика. 2012