Unitarian noun 2adjective 1forms 3 noun2 •A follower of Unitarian Universalism or a similar non-creedal (non-dogmatic) religion (either Christian or non-Christian) that originated historically from Christian Unitarianism.The Unitarians never kneel. But I want to kneel. — 2020 •A member of a political movement advocating a unitary state rather than a federal one, especially the Unitarios of nineteenth century Argentina (known as the Unitarian Party in English). adjective1 •Pertaining to Unitarianism.It was no less than whether the psychic movement in Britain was destined to take a Unitarian or a Trinitarian course. — 1925 formsUnitarians · more Unitarian · most Unitarian