"plainly illogical," 1550s, from French absurde (16c.), from Latin absurdus "out of tune, discordant;" figuratively "incongruous, foolish, silly, senseless," from ab- "off, away from," here perhaps an intensive prefix, + surdus "dull, deaf, mute," which is possibly from an imitative PIE root meaning "to buzz, whisper" (see susurration). Thus the basic sense is perhaps "out of tune," but de Vaan writes, "Since 'deaf' often has two semantic sides, viz. 'who cannot hear' and 'who is not heard,' ab-surdus can be explained as 'which is unheard of' ..." The modern English sense is the Latin figurative one, perhaps "out of harmony with reason or propriety." Related: Absurdly; absurdness.
late 15c., absurdite, "that which is absurd," from Late Latin absurditatem (nominative absurditas) "dissonance, incongruity," noun of state from Latin absurdus "out of tune;" figuratively "incongruous, silly, senseless" (see absurd).
1785, an absurd perversion of (Welsh) rabbit, as if from rare (adj.) + bit (n.). See Welsh.
1670s, "absurd thing, object of mockery or contempt;" 1680s, "words or actions meant to invoke ridicule or excite laughter at someone's expense," from French ridicule, noun use of adjective (15c.), or from Latin ridiculum "laughing matter, a joke, a jest," noun use of neuter of ridiculus "laughable, funny, absurd," from ridere "to laugh" (see risible).
"He who brings ridicule to bear against truth, finds in his hand a blade without a hilt." [Walter Savage Landor, "Imaginary Conversations"]
1540s, "contrary to nature, reason, or common sense," from Latin praeposterus "absurd, contrary to nature, inverted, perverted, in reverse order," literally "before-behind" (compare topsy-turvy,cart before the horse), from prae "before" (see pre-) + posterus "subsequent, coming after," from post "after" (see post-).
The sense gradually shaded into "foolish, ridiculous, stupid, absurd." The literal meaning "reversed in order or arrangement, having that last which ought to be first" (1550s) is now obsolete in English. In 17c. English also had a verb preposterate "to make preposterous, pervert, invert." Related: Preposterously; preposterousness.