Sufism or Taṣawwuf (Arabic: الْتَّصَوُّف "sect"; personal noun: صُوفِيّ ṣūfiyy/ṣūfī, مُتَصَوّف mutaṣawwuf), which is often defined as "Islamic mysticism", "the inward dimension of Islam", or "the phenomenon of mysticism within Islam", is a mystical trend in Islam "characterized ... [by particular] values, ritual practices, doctrines and institutions" which began very early in Islamic history and represented "the main manifestation and the most important and central crystallization of" mystical practice in Islam.
Practitioners of Sufism have been referred to as "Sufis" (Arabic plurals: صُوفِيَّة ṣūfiyyah; صُوفِيُّون ṣūfiyyūn; مُتَصَوُّفََة mutaṣawwufah; مُتَصَوُّفُون mutaṣawwufūn), an Arabic word which is believed by historians to have originally indicated the "woollen clothes (ṣūf) or rough garb" worn by the early Islamic mystics. Historically, they have often belonged to different ṭuruq or "orders"—congregations formed around a grand master referred to as a mawla who traces a direct chain of 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."Rumi stated: "The Sufi is hanging on to Muhammad, like Abu Bakr." Sufis regard Muhammad as al-Insān al-Kāmil, the primary perfect man who exemplifies the morality of God, and regard Muhammad as their leader and prime spiritual guide.
All Sufi orders trace many of their original precepts from Muhammad through his son-in-law Ali with the notable exception of the Naqshbandi, who claim to trace their origins from Muhammad through the first Rashid Caliph, 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. Most of them follow one of the four madhhabs (jurisprudential schools of thought) of Sunni Islam and maintain a Sunni aqidah (creed).