antediluvian

adjective

an·​te·​di·​lu·​vi·​an ˌan-ti-də-ˈlü-vē-ən 

-(ˌ)dī-

1

: of or relating to the period before the flood described in the Bible

2

a

: 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

antediluvian noun

Did you know?

Before there was antediluvian, there were the Latin words ante (meaning "before") and diluvium (meaning "flood"). In the 1600s, English speakers were using antediluvian to describe conditions they believed existed before the great flood described in the biblical account of Noah and the ark. By the early 1700s, the word had come to be used as both an adjective and a noun referring to anything or anyone prodigiously old. Naturalist Charles Darwin used it to characterize the mighty "antediluvian trees" some prehistoric mammals might have used as a food source, and in his American Notes, Charles Dickens described an elderly lady who informed him, "It is an extremely proud and pleasant thing … to be an antediluvian."

Synonyms

• age-old
• aged
• ancient
• antique
• dateless
• hoar
• hoary
• immemorial
• old
• venerable

Examples of antediluvian in a Sentence

He has antediluvian notions about the role of women in the workplace.

found evidence in the Middle East of an antediluvian people previously unknown to history

Recent Examples on the Web

Not a bad start, definitely auspicious, which makes the antediluvian inspirations behind these sparkling party dresses all the more mysterious. —Rachel Elspeth Gross, Forbes.com, 15 June 2025

Image Still, Professor Bogdanor said, the antediluvian nature of the Lords eroded faith in government generally, particularly among young people. —Mark Landler, New York Times, 24 Dec. 2024

Eliminating antediluvian student loan debts held by vulnerable older adults seems both just and good public policy. —Next Avenue, Forbes, 11 Oct. 2024

Glory be to god for logjams, the antediluvian dark, for being a supply of goodness outpacing demand because so many prefer their egos’ endless ranting to the suggestion of a different narrator or narrative. —Virginia Konchan, The New Yorker, 30 Sep. 2024

Word History

Etymology

borrowed from New Latin antedīluviānus, from Latin ante- ante- + dīluvium "flood, inundation" + -ānus -an entry 2 — more at deluge entry 1

First Known Use

1646, in the meaning defined at sense 1

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Kids Definition

antediluvian

adjective

an·​te·​di·​lu·​vi·​an ˌant-i-də-ˈlü-vē-ən 

-dī-

1

: of or relating to the period before the Flood described in the Bible

2

: very old or old-fashioned

antediluvian noun