Naskh (نسخ) is an Arabic word usually translated as "abrogation". In tafsir, or Islamic legal exegesis, naskh recognizes that one rule might not always be suitable for every situation. In the widely recognized and "classic" form of naskh, one ḥukm "ruling" is abrogated to introduce an exception to the general rule, but the text the ḥukm is based on is not repealed.
Some examples of Islamic rulings based on naskh include a gradual ban on consumption of alcohol (originally alcohol was not banned, but Muslims were told that the bad outweighed the good in drinking) and a change in the direction of the qibla, the direction that should be faced when praying salat (originally Muslims faced Jerusalem, but this was changed to face the Kaaba in Mecca).
With few exceptions, Islamic revelations do not state which Quranic verses or hadith have been abrogated, and Muslim exegetes and jurists have disagreed over which and how many hadith and verses of the Quran are recognized as abrogated, with estimates varying from less than ten to over 500.
Other issues of disagreement include whether the Quran, the central religious text of Islam, can be abrogated by the Sunnah, the body of traditional social and legal custom and practice of the Islamic community, or vice versa — a disagreement in Sunni Islam between the Shafiʽi and Hanafi schools of fiqh "jurisprudence"; and whether verses of the Quran may be abrogated at all, instead of reinterpreted and more narrowly defined — an approach favored by a minority of scholars.
Several ayat (Quranic verses) state that some revelations have been abrogated and superseded by later revelations, and narrations from Muhammad's companions mention abrogated verses or rulings of the religion. The principle of abrogation of an older verse by a new verse in the Quran, or within the hadiths is an accepted principle of all four Sunni madhāhib, or schools of fiqh, and was an established principle in Sharia by at least the 9th century.