Theologian vs. Theologist — Which is Correct Spelling?

One who is learned in theology.

One who studies theology.

In Roman Catholic usage, a theological lecturer attached to a cathedral church.

In Eastern Orthodox usage, a person who has had direct experience of and unity with God.

A person well versed in theology; a professor of theology or divinity; a divine.

Someone who is learned in theology or who speculates about theology (especially Christian theology)