One who is captious, fallacious, or deceptive in argument.
One of a class of teachers of rhetoric, philosophy, and politics in ancient Greece.
A teacher who uses plausible but fallacious reasoning.
One who believes dogmatically in something regardless of evidence or even conclusive proof that the thing is false or was staged; one who has true-believer syndrome.
Used other than figuratively or idiomatically: see true, believer.
A strict follower of a doctrine.