<p><strong>Noun</strong></p><ul><li>A person who maintains that God is one being, rejecting the doctrine of the Trinity.</li><li><em>(initial capital letter)</em> A member of a liberal religious denomination founded upon the doctrine that God is one being, and giving each congregation complete control over its affairs.</li><li>An advocate of unity or centralization, as in government.</li></ul><p><strong>Adjective</strong></p><ul><li><em>(initial capital letter)</em> Pertaining to the Unitarians or their doctrines; accepting Unitarianism; belonging to the Unitarians.</li><li>Unitary.</li></ul>