Sufism, or Taṣawwuf (Arabic: الْتَّصَوُّف), variously defined as "Islamic mysticism", "the inward dimension of Islam" or "the phenomenon of mysticism within Islam", is mysticism in Islam, "characterized ... [by particular] values, ritual practices, doctrines and institutions" which began very early in Islamic history and represents "the main manifestation and the most important and central crystallization of" mystical practice in Islam. Practitioners of Sufism have been referred to as "Sufis" (from صُوفِيّ ṣūfiyy / ṣūfī).
Historically, Sufis have often belonged to different ṭuruq or "orders" – congregations formed around a grand master referred to as a wali who traces a direct chain of successive teachers back to the Islamic prophet, Muhammad. These orders meet for spiritual sessions (majalis) in meeting places known as zawiyas, khanqahs or tekke. They strive for ihsan (perfection of worship), as detailed in a hadith: "Ihsan is to worship Allah as if you see Him; if you can't see Him, surely He sees you." Sufis regard Muhammad as al-Insān al-Kāmil, the primary perfect man who exemplifies the morality of God, and see him as their leader and prime spiritual guide.
All Sufi orders trace most of their original precepts from Muhammad through his cousin and son-in-law Ali, with the notable exception of the Naqshbandi order, who trace their original precepts to Muhammad through his companion and father-in-law, Abu Bakr.
Although the overwhelming majority of Sufis, both pre-modern and modern, were and are adherents of Sunni Islam, there also developed certain strands of Sufi practice within the ambit of Shia Islam during the late medieval period, particularly after the forced conversion of Iran from majority Sunni to Shia. Traditional Sufi orders during the first five centuries of Islam were all based in Sunni Islam. Although Sufis were opposed to dry legalism, they strictly observed Islamic law and belonged to various schools of Islamic jurisprudence and theology.
Sufis have been characterized by their asceticism, especially by their attachment to dhikr, the practice of remembrance of God, often performed after prayers. They gained adherents among a number of Muslims as a reaction against the worldliness of the early Umayyad Caliphate (661–750)and have spanned several continents and cultures over a millennium, initially expressing their beliefs in Arabic and later expanding into Persian, Turkish, and Urdu, among others. Sufis played an important role in the formation of Muslim societies through their missionary and educational activities. According to William Chittick, "In a broad sense, Sufism can be described as the interiorization, and intensification of Islamic faith and practice."
Despite a relative decline of Sufi orders in the modern era and criticism of some aspects of Sufism by modernist thinkers and conservative Salafists, Sufism has continued to play an important role in the Islamic world, and has also influenced various forms of spirituality in the West.
The Arabic word tasawwuf (lit. being or becoming a Sufi), generally translated as Sufism, is commonly defined by Western authors as Islamic mysticism. The Arabic term sufi has been used in Islamic literature with a wide range of meanings, by both proponents and opponents of Sufism. Classical Sufi texts, which stressed certain teachings and practices of the Quran and the sunnah (exemplary teachings and practices of the Islamic prophet Muhammad), gave definitions of tasawwuf that described ethical and spiritual goals[note 1] and functioned as teaching tools for their attainment. Many other terms that described particular spiritual qualities and roles were used instead in more practical contexts.
Some modern scholars have used other definitions of Sufism such as "intensification of Islamic faith and practice" and "process of realizing ethical and spiritual ideals".
The term Sufism was originally introduced into European languages in the 18th century by Orientalist scholars, who viewed it mainly as an intellectual doctrine and literary tradition at variance with what they saw as sterile monotheism of Islam. In modern scholarly usage the term serves to describe a wide range of social, cultural, political and religious phenomena associated with Sufis.