Antediluvian means "before the flood" — that is, the Biblical flood with Noah's ark. Generally, though, the word is used — often humorously — to describe something really, really old.

In popular language, antediluvian is almost always used to exaggerate how comically, ridiculously old and out-of-date something is. You may laugh at your parents' antediluvian ideas of what's proper for going out on a date. And how about those antediluvian computers they still insist are fine! When the word was coined in the seventeenth century, however, it was meant literally. Back then, the science of reconstructing the Earth's history used the Bible as a frame of reference.

Definitions of antediluvian

adj of or relating to the period before the biblical flood

antediluvian man”

adj so extremely old as seeming to belong to an earlier period

“a ramshackle antediluvian tenement”
antediluvian ideas”
antiquated, archaic
of long duration; not new

n any of the early patriarchs who lived prior to the Noachian deluge

antediluvian patriarch
Type of:
any of the early biblical characters regarded as fathers of the human race

n a very old person

Type of:
golden ager, old person, oldster, senior citizen
an elderly person

Sign up, it's free!

Whether you're a student, an educator, or a lifelong learner, can put you on the path to systematic vocabulary improvement.