About 5% (by membership) of Protestant denominations minimize or reject outright the language of the 4th century Catholic-Orthodox Trinitarian formulations.
Instead, what they teach is the Bible, which does not include such terms as "God the Son," "God the Holy Spirit," "fully God and fully man" -- or any of the other technical Trinitarian language adopted after the Official Church was made the State Religion of the Roman Empire, beginning in the 4th century.
Unitarians originally fell into the category of anti-Trinitarian Christians.
Today they are barely recognizable as Christians, but in their own minds, at least, they revere Christ second only to God.
Five US presidents were Unitarians: John Adams, Thomas Jefferson, John Quincy Adams, Millard Fillmore and William Howard Taft.
Jefferson, the alleged "father" of the "wall of separation" between Church and State, is particularly noted for organizing and attending Christian church services in the US Capitol building.
Thanks BroJoeK!