antediluvian (adj.)

late 14c., "an overflowing of water, a great flood, Noah's Flood in Genesis," from Old French deluge (12c.), earlier deluve, from Latin diluvium "flood, inundation," from diluere "wash away," from dis- "away" (see dis-) + -luere, combining form of lavere "to wash" (from PIE root *leue- "to wash"). Figurative sense of "anything that overflows or floods" is from early 15c.

After me the deluge (F. après moi le déluge), a saying ascribed to Louis XV, who expressed thus his indifference to the results of his policy of selfish and reckless extravagance, and perhaps his apprehension of coming disaster. [Century Dictionary]

Proto-Indo-European root meaning "front, forehead," with derivatives meaning "in front of, before; end." Also see *ambhi-.

It forms all or part of: advance; advantage; along; ancestor; ancient (adj.); answer; Antaeus; ante; ante-; ante meridiem; antecede; antecedent; antedate; antediluvian; ante-partum; antepenultimate; anterior; anti-; antic; anticipate; anticipation; antique; antler; avant-garde; elope; end; rampart; un- (2) prefix of reversal; until; vambrace; vamp (n.1) "upper of a shoe or boot;" vanguard.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit antah "end, border, boundary;" Hittite hanti "opposite;" Greek anta, anten "opposite," anti "over against, opposite, before;" Latin ante (prep., adv.) "before (in place or time), in front of, against;" Old Lithuanian anta "on to;" Gothic anda "along;" Old English and- "against;" German ent- "along, against."