Sufism (Arabic: الصُّوفِيَّة‎ aṣ-ṣūfiyya), also known as Tasawwuf (التَّصَوُّف‎ at-taṣawwuf), is a mystic body of religious practice, found mainly within Sunni Islam but also within Shia Islam, which is characterized by a focus on Islamic spirituality, ritualism, asceticism and esotericism. It has been variously defined as "Islamic mysticism", "the mystical expression of Islamic faith", "the inward dimension of Islam", "the phenomenon of mysticism within Islam", the "main manifestation and the most important and central crystallization" of mystical practice in Islam, and "the interiorization and intensification of Islamic faith and practice".