subunist
/ˌsʌbˈjuːnɪst/Theology rare
noun
A person who upholds the sacrament of the Eucharist in one of its elements (either bread or wine) only; specifically a member of a party in 15th cent. Bohemia which defended the practice of communion of this sort against the Utraquists.
Origin
Late 19th century. From post-classical Latin sub una (in sub una specie under one kind; from classical Latin sub + ūnā, ablative feminine of ūnus + speciē, ablative of speciēs) + -ist.