One who believes that Jesus will reign over Earth for a thousand years.(noun)
A millenarian.(noun)
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Use "chiliast" in a sentence
"It is worth noting that, as befits a chiliast, Ghose never denies action."
"So with DARE’s classicist, George Goebel, the great lexicographer turned from Latin to Greek: deutero means “second” and chiliast refers to the biblical “kingdom of a thousand years.”"