A person who stubbornly holds to a philosophy or opinion regardless of its feasibility.
In France, in 1815-30, one of a school who desired a constitution like that of Britain.
Stubbornly holding on to an idea without concern for practicalities or reality.
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.