Definition of "antediluvian"

(biblical) Belonging or pertaining to, or existing in, the time prior to the great flood described in Genesis, or (by extension) to a great or destructive flood or deluge described in other mythologies.  quotations  examples

(by extension) Of animals and plants: long extinct; prehistoric.  quotations  examples

(figurative, hyperbolic, chiefly humorous)

1. Of a person or thing: very old; ancient.  quotations  examples

   Quotations

   • [H]is eldest son Bo-bo, […] let some sparks escape into a bundle of straw, which kindling quickly, spread the conflagration over every part of their poor mansion, till it was reduced to ashes. Together with the cottage (a sorry antediluvian make-shift of a building, you may think it), what was of much more importance, a fine litter of new-farrowed pigs, no less than nine in number, perished.

     1823, Elia [pseudonym; Charles Lamb], “A Dissertation upon a Roast Pig”, in Elia. Essays which have Appeared under that Signature in The London Magazine, London: […] [Thomas Davison] for Taylor and Hessey, […], page 277

   • There was an antediluvian tradition (much older than Shakespeare) that on Midsummer's Night young people should go with lanterns, and a fiddler, and a keg or two of cider, to a patch of turf known as Donkey's Green in the heart of the woods and there celebrate the solstice with dancing.

     1969 November 10, John Fowles, chapter 12, in The French Lieutenant’s Woman, 1st US edition, Boston, Mass.; Toronto, Ont.: Little, Brown and Company […], page 90

   • The air inside smelled antediluvian, regal somehow, with traces of pipe tobacco, tea leaves, cooking sherry, and the earthen aroma of stone architecture.

     2003, Dan Brown, chapter 54, in The Da Vinci Code, [London]: BCA, published 2005, page 226

   • If we agree with [Allan] Blinder's assessment, we must acknowledge the pressing need to inject new ideas into an old system—a system so antediluvian that it is, remarkably, still based on the agrarian calendar.

     2010, Sam Chaltain, “Connect (or, Make the Connections that Let You ‘See the Whole Board’)”, in American Schools: The Art of Creating a Democratic Learning Community, Lanham, Md.: Rowman & Littlefield Education, page 41

2. Of attitudes, ideas, etc.: extremely old-fashioned, especially to a laughable extent; antiquated.  quotations  examples

   Quotations

   • If, by any miſchance, and in an evil hour, ſome country couſin, not knovving my vvays, or ſome antediluvian prig, not minding them, happen to fall upon me vvith formal ſpeeches, vvhere I can make no eſcape, a fit of yavvning takes me immediately, and I am demoliſhed for the reſt of the day.

     1796, [Frances Burney], “A Chat”, in Camilla: Or, A Picture of Youth. […], volume III, London: […] T[homas] Payne, […]; and T[homas] Cadell Jun. and W[illiam] Davies (successors to Mr. [Thomas] Cadell) […], book V, pages 78–79

   • Portions of the ruling reflected the court's culturally conservative roots, stating that because marriage is only for reproduction, LGBTQ relationships are unnatural because they cannot produce children. […] The ruling continued in its surprisingly antediluvian rationale, invalidating untold numbers of nontraditional families.

     2021 December 3, “LGBTQ Couples, Families and Marriage are ‘against the Natural Order,’ Thai Constitutional Court Rules”, in Coconuts Bangkok‎, Bangkok, Thailand: Coconuts Media, archived from the original on 2023-03-19

(biblical) A person who lived in the time prior to the great flood described in Genesis, especially one of the biblical patriarchs.  examples

(figurative, hyperbolic, chiefly humorous)

1. A very old person.  quotations  examples

   Quotations

   • From what cursed old antediluvian, who lived before the invention of the spinning-jennies, she learned this craft, Heaven only knows; […]

     1823 December 23 (indicated as 1824), [Walter Scott], “Discussion”, in St Ronan’s Well. […], volume III, Edinburgh: […] [James Ballantyne and Co.] for Archibald Constable and Co.; London: Hurst, Robinson, and Co., pages 134–135

   • He was a boy in form, and an antediluvian in feature. Some thought […] that he was really and truly a Brownie.

     1828 October, the Ettrick Shepherd [pseudonym; James Hogg], “The Brownie of the Black Haggs”, in Blackwood’s Edinburgh Magazine, volume XXIV, number CXLIV, Edinburgh: William Blackwood, […]; London: T[homas] Cadell, […], page 494, column 1

2. A person with extremely old-fashioned attitudes, ideas, etc., especially to a laughable extent; a fogey or old fogey.  examples