Which is correct: psuedo-Christian or psuedo Christian?

This rule is not set in stone -- but --

if pseudo-Christian is used as an adjective -- as in "pseudo-Christian politician" -- the hyphen is used.

If pseudo Christian is used as a noun -- as in "a pseudo Christian is running for office" -- the hyphen is not used.

OK, thanks!

You're welcome.

The correct spelling is "pseudo-Christian". When it comes to compound words or phrases, the general rule is to use a hyphen when two or more words are combined to form a single adjective before a noun. In this case, "pseudo" and "Christian" are combined to describe a person or a belief that is not genuinely or authentically Christian. Therefore, the hyphen is used to link the two words together, resulting in "pseudo-Christian".