noun

1. a person who denies the doctrine of the Trinity, accepting the moral teachings, but rejecting the divinity, of Jesus, and holding that God exists as one person or being
2. a member of a denomination based on these beliefs and characterized by congregational autonomy, tolerance of differing religious views, absence of creed, etc.
   in full Unitarian Universalist

Etymology: < ModL unitarius, unitary + -an: also in part < unit(y) + -arian

adjective

1. of Unitarians or their doctrines, or adhering to Unitarianism
2. unitary