Wikipedia
Kashf "unveiling" is a Sufi concept rooted in Gnostic ideals dealing with knowledge of the heart rather than of the intellect. Kashf describes the state of experiencing a personal divine revelation after ascending through spiritual struggles, and uncovering the heart (a spiritual faculty) in order to allow divine truths to pour into it. Kashf is etymologically related to mukashafa “disclosure”/ “divine irradiation of the essence”, which connotes “gain[ing] familiarity with things unseen behind the veils”. For those who have purified their hearts, and who come to know the Divine Names and Attributes to the fullest of their individual capacities, the veils in front of the purely spiritual realms are opened slightly, and they begin to gain familiarity with the unseen. In Sufism, an even further revelatory capacity exists by which the Divine mysteries become readily apparent to the seeker through the light of knowledge of God. This is called tajalli "manifestation".