Definition of millenarians:
(adj) :
(Christianity) Pertaining to the belief in an impending period of one thousand years of peace and righteousness associated with the Second Coming of Christ and his reign on earth.
(adj) :
Pertaining to any of various religious or social movements which believe in a coming or ongoing radical change to existing world order.
(n) :
A person who believes in an apocalyptic millennium.
(adj) :
Lasting or expected to last a thousand years.