acephali
/(ˌ)eɪˈsɛfəlʌɪ/ /(ˌ)eɪˈsɛf(ə)lʌɪ/ /(ˌ)eɪˈkɛfəlʌɪ/noun
1 Church History. With capital initial. A group of extreme Monophysites who seceded from the main body in the 5th cent., acknowledging no leaders and rejecting episcopal control. Also in singular, in form Acephalus: a member of such a group.
2An (imaginary) race of headless people.
Origin
Old English (in an earlier sense). From post-classical Latin acephali (plural) members of a sect with no acknowledged leaders, priests not subordinate to a bishop (636 in Isidore), people with no feudal superior except the king, (imaginary) race of headless people, use as noun of masculine plural of classical Latin acephalus.