Qutb, Qutub, Kutb, or Kutub (Arabic: قطب), literally means 'axis', 'pivot' or 'pole'. Qutb can refer to celestial movements and used as an astronomical term or a spiritual symbol. In Sufism, a Qutb or Kutb is the perfect human being, al-insān al-kāmil, who leads the saintly hierarchy. The Qutb is the Sufi spiritual leader that has a Divine connection with God and passes knowledge on which makes him central to (or the axis of) Sufism, but he is unknown to the world. There is only one Qutb per era and he is an infallible and trusted spiritual leader. He is only revealed to a select group of mystics because there is a "human need for direct knowledge of God".
According to the Institute of Ismaili Studies (Ismailism is a branch of Shīʻa Islam), "In mystical literature, such as the writings of al–Tirmidhi, Abd al–Razzaq and Ibn al–‘Arabi (d. 1240), refers to the most perfect human being (al–insan al–kamil) who is thought to be the universal leader of all saints, to mediate between the divine and the human and whose presence is deemed necessary for the existence of the world."
Read more about Qutb: Scriptural Evidence of Qutb, The Cosmic Hierarchy of The Qutb, People Named Qutb or Qutb-ud-din, Buildings, Things