Consisting of a thousand years; of or pertaining to the millennium, or to the Millenarians.

One who believes that Christ will personally reign on earth a thousand years; a Chiliast.

a person who believes in the coming of the millennium (a time of great peace and prosperity)

Apocalyptic; forecasting the ultimate destiny of the world; foreboding imminent disaster or final doom; wildly unrestrained; ultimately decisive. From Merriam -Webster's

Referring to more extreme millennial expectations, in which belief in an imminent apocalyptic transformation tends to spur the faithful into action, often of a violent nature.