thumb|270px|right|A Haredi Hasidic family walking in [[Brooklyn, New York City]]
Haredi Judaism (, ) is a sector of Orthodox Judaism that is characterized by its strict interpretation of religious sources and its accepted (Jewish law) and traditions, in opposition to more accommodating values and practices. Its members are often referred to as ultra-Orthodox in English, a term considered pejorative by many of its adherents, who prefer the term strictly Orthodox or Haredi (plural: Haredim). Haredim regard themselves as the most authentic custodians of Jewish religious law and tradition which, in their opinion, is binding and unchangeable. Many consider all other contemporary expressions of Judaism, including Modern Orthodoxy, as "deviations from God's laws", although other movements of Judaism would disagree.
Some scholars have suggested that Haredi Judaism is a reaction to societal changes, including political emancipation, the movement derived from the Enlightenment, acculturation, secularization, religious reform in all its forms from mild to extreme, and the rise of the Jewish national movements. In contrast to Modern Orthodox Jews, Haredim segregate themselves from other parts of society, although some Haredi communities encourage young people to get a professional degree or establish a business. Furthermore, some Haredi groups, like Chabad-Lubavitch, encourage outreach to non-observant and unaffiliated Jews.
As of 2020, there were about 2.1 million Haredim globally, representing 14% of the world's Jewish population. Haredim primarily live in Israel (17% of Israeli Jews and 14% of Israel's total population), North America (12% of American Jews), and Western Europe (most notably Antwerp and Stamford Hill in London). Absence of intermarriage, coupled with both a high birth and retention rate, spur rapid growth of the Haredi population, which is on pace to more than double every 20 years. Their numbers have been further boosted since the 1970s by secular Jews adopting a Haredi lifestyle as part of the baal teshuva movement; however, this has been somewhat offset by those leaving.
Terminology
thumb|Young Haredi Jews in Jerusalem, 2005
The term is a Modern Hebrew adjective derived from the Biblical verb , which appears in the Book of Isaiah (; its plural appears in Isaiah ) and is translated as "[one who] trembles" at the word of God. The word connotes an awe-inspired fear to perform the will of God; it is used to distinguish them from other Orthodox Jews (similar to the names used by Christian Quakers and Shakers to describe their relationship to God).
The term most commonly used by outsiders, for example most American news organizations, is ultra-Orthodox Judaism. Hillel Halkin suggests the origins of the term may date to the 1950s, a period in which Haredi survivors of the Holocaust first began arriving in America. However, Isaac Leeser (1806–1868) was described in 1916 as "ultra-Orthodox".
The word Haredi is often used in the Jewish diaspora in place of the term ultra-Orthodox, which many view as inaccurate or offensive, it being seen as a derogatory term suggesting extremism; English-language alternatives that have been proposed include fervently Orthodox, strictly Orthodox, or traditional Orthodox.
Haredi Jews also use other terms to refer to themselves. Common Yiddish words include (Jews), (virtuous Jews), and more rarely, (blacks), a reference to the black clothes they typically wear; a related informal term used in English is black hat.
Population
Due to its imprecise definition, lack of data collection, and rapid change over time, estimating the global Haredi population is difficult. The true number of Haredim may be significantly underestimated due to their reluctance to participate in surveys and censuses.
In 1992, out of a total of 1,500,000 Orthodox Jews worldwide, about 550,000 were Haredi (half of them in Israel). One estimate given in 2011 stated that there were approximately 1.3 million Haredi Jews globally. Studies have shown a very high growth rate, with a large young population. Haredi population grew to 2.1 million in 2020 and is expected to double by 2040. Not all leave the Orthodox community, as some become more behaviorally modern while still practicing some form of Orthodoxy.