Definition of antediluvian
1 : of or relating to the period before the flood described in the Bible
2a : made, evolved, or developed a long time ago
an antediluvian automobile that antediluvian relic known as a slide rule
b : extremely primitive or outmoded
an antediluvian prejudice antediluvian in his politics
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Time Traveler for antediluvian
The first known use of antediluvian was in 1646
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