A person who lays down principles as incontrovertibly true without considering evidence or other viewpoints; someone rigidly attached to a belief system.
From dogma + -ist (suffix denoting an adherent of a practice/belief). First appeared in English philosophical texts in the 1600s to describe rigid thinkers.
The amusing irony: even skeptics can become dogmatists about skepticism—it's a universal human tendency to stop thinking once we feel certain about something!
Complete word intelligence in one call. Free tier — 50 lookups/day.