The Athinganoi (Ancient Greek: , singular Athinganos, ) were a 9th-century sect of Monarchians located in Phrygia, founded by Theodotus the Banker. The etymology of the word is not certain, but a common determination is a derivation in Greek for "(the) untouchables" derived from a privative alpha prefix and the verb thingano (, "thinganein", "to touch"). It is uncertain whether the sect survived beyond the 9th century. They were probably scattered across Anatolia and the Balkans following the destruction of the Paulician capital Tephrike in the 870s.
An earlier, and probably quite distinct, sect with the same name is refuted by Marcus Eremita, who seems to have been a disciple of St. John Chrysostom. His book Eis ton Melchisedek, or according to Photius "Against the Melchisedekites", speaks of these new teachers as making Melchisedech an incarnation of the Logos (divine Word).
They were anathematized by the bishops, but would not cease to preach. They seem to have been otherwise orthodox. St. Jerome (Ep. 73) refutes an anonymous work which identified Melchisedech with the Holy Ghost. About AD 600, Timotheus, Presbyter of Constantinople, in his book De receptione Haereticorum adds at the end of his list of heretics who need rebaptism the Melchisedechians, "now called Athingani. They live in Phrygia, and are neither Hebrews nor Gentiles. They keep the Sabbath, but are not circumcised. They will not touch any man. If food is offered to them, they ask for it to be placed on the ground; then they come and take it. They give to others with the same precautions."
The name athinganoi, later variant form of which is atsinganoi, came to be associated with the Romani people who first appeared in the Byzantine Empire at the time and is the root word for "cigano", "çingene", "zigeuner", "tzigan", "?igan", and "zingaro", words used to describe members of the Romani people. Today many of these words are still used in a derogatory sense, albeit others are the most common exonym for them in a given language. It is still not clear if the athinganoi who were present in the 9th century in Europe are related to the Romani people of today.