In Sufi philosophy, a mast (pronounced "must") is a person who is overwhelmed with love for God, accompanied with external disorientation resembling intoxication. The word is coined by Meher Baba and originates from the Sufi term mast-Allah meaning "intoxicated with God" from Persian mast, lit. "intoxicated." Another interpretation of its origin is that it is derived from masti, a Persian word meaning "overpowered."
Mast (Sufism) Wikipedia
According to Meher Baba, a mast is one who is entranced or spellbound by internal spiritual experiences and ecstasies, who cannot function outwardly in an ordinary way, and may appear mad to a casual outside observer. Such experiences, according to Meher Baba, stem from the station of a mast's consciousness (his or her state of consciousness) on inner planes of involution. In the book, The Wayfarers: Meher Baba With the God-Intoxicated, British medical doctor William Donkin documents in great detail Meher Baba's numerous contacts with masts throughout South Asia (mostly Iran, India, and Pakistan). The introduction, written by Meher Baba, explains their unique state and their outward characteristics. Meher Baba carefully distinguishes the mast state from madness, saying that in the case of the mad person, the mind is sped up, while in the case of the mast it is slowed down. Meher Baba also made a Sufi analogy (reflecting the poetry of Hafez) to the drunkenness of one intoxicated with wine, but in this case the wine is the love of God. Meher Baba contacted thousands of masts all over India, Pakistan, and Iran, saying that he was freeing them from enchantment and helping them to continue on the spiritual path and to be of inward service to humanity.
Masts can be in varying degrees of the states of salik or majzoob. Salik means more in touch with outward surroundings -- grounded and ordinary. Majzoob refers to that state of being immersed in the inner plane and divorced from the outside world.