Lit. “Langour,” or “Intermission”. (1) The interval between the supposed revelation of the xcvith Surah of the Qur’an and the lxxivth and xciiird Surahs. It is during this period that the powers of inspiration of the Prophet are said to have been suspended, and it was then that he contemplated suicide by intending to cast himself from Mount Hira. The accounts of this interval are confused and contradictory, and various are the periods assigned to it, viz. from seven months to seven years.
(2) The term is also used for the time which elapses between the disappearance of a prophet and the appearance of another. (Ghiyasu ‘l-Lughah in loco)
(3) A term used by Sufi mystics for a declension in spiritual life. (‘Abdu ‘r-Razzaq’s Dict. of Sufi Terms)
Based on Hughes, Dictionary of Islam