Definition for Preposterous:

• Contrary to nature, reason, or common sense; perverse, foolish; absurd. Hence preposterously adv. preposterousness n. [ Latin]

Synonyms for Preposterous:

• adj.

  •absurd (adjective)
  • self-contradictory,
  • foolish,
  • invalid,
  • senseless,
  • incongruous,
  • illogical,
  • meaningless,
  • screwy,
  • anachronistic,
  • absurd,
  • impossible,
  • fallacious,
  • goofy,
  • paradoxical,
  • inconsistent,
  • idiotic,
  • eccentric,
  • ridiculous,
  • irrational,
  • unusual,
  • inane,
  • contradictory,
  • ludicrous,
  • bizarre,
  • crazy,
  • farcical,
  • nonsensical,
  • silly,
  • loony,
  • stupid,
  • outlandish,
  • implausible.
  •balmy (adjective)
  • potty.
  •egregious (adjective)
  • egregious.
  •exaggerated (adjective)
  • pretentious.
  •extreme (adjective)
  • extreme.
  •foolish (adjective)
  • zany,
  • tomfool,
  • witless,
  • ill-considered,
  • dippy,
  • imbecilic,
  • loopy.
  •harebrained (adjective)
  • flighty,
  • mindless.
  •impossible (adjective)
  • unrealizable,
  • unworkable,
  • contrary to reason,
  • unattainable.
  •improper (adjective)
  • unbefitting,
  • Unapt.
  •insane (adjective)
  • loco,
  • balmy,
  • moonstruck.
  •ridiculous (adjective)
  • dubious,
  • comical,
  • absurd,
  • farcical,
  • poppycock,
  • crazy,
  • foolish,
  • nonsensical,
  • incredible,
  • outlandish,
  • silly,
  • weird,
  • outrageous,
  • grotesque,
  • curious,
  • ridiculous,
  • ludicrous,
  • laughable,
  • eccentric,
  • bizarre,
  • oddball.
  •ridiculous, bizarre (adjective)
  • foolish,
  • harebrained,
  • out of the question,
  • crazy,
  • far-out,
  • taking the cake,
  • senseless,
  • nonsensical,
  • unthinkable,
  • extreme,
  • outrageous,
  • unbelievable,
  • shocking,
  • irrational,
  • excessive,
  • monstrous,
  • ludicrous,
  • wild,
  • incredible,
  • stupid,
  • fantastic,
  • silly,
  • unusual,
  • extravagant,
  • wacky,
  • laughable,
  • thick,
  • insane,
  • impossible,
  • unreasonable,
  • asinine,
  • absurd,
  • exorbitant,
  • too much.
  •softheaded (adjective)
  • softheaded.
  •unbelievable (adjective)
  • farfetched,
  • fantastic,
  • incredible,
  • beyond belief,
  • implausible,
  • open to doubt.
  •unheard-of (adjective)
  • unheard-of.
  •wacky (adjective)
  • hare-brained.

• n.

  •
  • childish.
  •
  • loony,
  • jerky,
  • dippy,
  • tomfool,
  • unearthly,
  • loopy,
  • zany,
  • balmy,
  • mad,
  • dopey,
  • lunatic,
  • sappy,
  • wacky,
  • softheaded,
  • insane,
  • harebrained,
  • moronic.
  •
  • shocking,
  • obscene,
  • unconscionable.
  •preposterous (noun)
  • foolish,
  • nonsensical,
  • derisory,
  • absurd,
  • ridiculous,
  • laughable,
  • ludicrous.

• Other synonyms:

  •
  • loony,
  • softheaded,
  • jerky,
  • exaggerated,
  • wacky,
  • dippy,
  • loopy,
  • unnatural.
  •
  • harebrained,
  • moronic,
  • much,
  • extreme.
  •
  • lunatic,
  • dopey,
  • sappy,
  • zany,
  • obscene,
  • unconscionable.
  •
  • shocking,
  • insane,
  • unearthly.
  •
  • mad.
  •laughable
  • rich.
  •unsuitable
  • improper.
  •Other relevant words:
  • deviation,
  • Hyperbolical,
  • quixotic,
  • inflated,
  • bonkers,
  • half-witted,
  • quaint,
  • fantasque,
  • goofy,
  • nuts,
  • steep,
  • excessive,
  • hilarious,
  • chimerical,
  • immense,
  • puckish,
  • unperceptive,
  • disproportionate,
  • tang dynasty,
  • blind,
  • improbable,
  • swinging,
  • nitwit,
  • blunder,
  • extortionate,
  • unheard-of,
  • enormous,
  • outre,
  • loco,
  • erroneous,
  • asinine,
  • mythic,
  • undue,
  • aberrant,
  • uncalled-for,
  • unbelievable,
  • exacting,
  • Unreasoned,
  • whimsical,
  • unbefitting,
  • false,
  • shocking,
  • astonishing,
  • harebrained,
  • uncontained,
  • prohibitive,
  • Feeble-minded,
  • extravagant,
  • lunatic,
  • extreme,
  • peculiar,
  • Blague,
  • mirthful,
  • balmy,
  • singular,
  • fancy-woven,
  • would-be,
  • thoughtless,
  • pathetic,
  • bosh,
  • stupendous,
  • rigmarole,
  • irresponsible,
  • too much,
  • soused,
  • vapid,
  • thin,
  • prohibited,
  • suspect,
  • intolerable,
  • unwarranted,
  • thick,
  • extraordinary,
  • Pathetical,
  • unmerited,
  • dubitable,
  • high-flown,
  • warped,
  • overdone,
  • invalidity,
  • cockamamie,
  • inordinate,
  • nutty,
  • crocked,
  • Seemless,
  • disgraceful,
  • fault,
  • unjustified,
  • optimistic,
  • lightheaded,
  • grandiloquent,
  • unreasonable,
  • impracticable,
  • birthday,
  • starry-eyed,
  • facetious,
  • fatuous,
  • Unapt,
  • punning,
  • moronic,
  • pretentious,
  • gouge,
  • unrestrained,
  • fool,
  • stretched,
  • unconscionable,
  • misguided,
  • unmatched,
  • crackpot,
  • exorbitant,
  • jocose,
  • pixyish,
  • fey,
  • purposeless,
  • ungodly,
  • far-fetched,
  • gothic,
  • humorous,
  • ill-considered,
  • questionable,
  • flagrant,
  • amusing,
  • unscientific,
  • Weak-minded,
  • prodigious,
  • fictitious,
  • goosey,
  • jocular,
  • loony,
  • booby,
  • buffoonish,
  • dippy,
  • far-out,
  • unique,
  • madcap,
  • vast,
  • vacant,
  • forced,
  • ill-judged,
  • unfit,
  • fanciful,
  • dunce,
  • potty,
  • open to doubt,
  • overblown,
  • wild,
  • wacky,
  • rich,
  • inconceivable,
  • dissipated,
  • Gouging,
  • pie-eyed,
  • insupportable,
  • egregious,
  • barmy,
  • stilted,
  • vain,
  • unrealizable,
  • monstrous,
  • problematic,
  • vacuous,
  • slapstick,
  • futile,
  • inept,
  • overwrought,
  • funny,
  • loaded,
  • barred,
  • blockhead,
  • insane,
  • unentitled,
  • unjustifiable,
  • bubbleheaded,
  • derisory,
  • brainless,
  • unreal,
  • ineffectual,
  • sloshed,
  • notional,
  • beyond belief,
  • useless,
  • unacceptable,
  • unconvincing,
  • risible,
  • much,
  • Unpractical,
  • unsubstantial,
  • foolhardy,
  • cuckoo,
  • obscene,
  • nonsense,
  • fancy,
  • increase,
  • skyrocketing,
  • macaronic,
  • fishy,
  • pointless,
  • problematical,
  • spiraling,
  • exaggerated,
  • lunkheaded,
  • unattainable,
  • Highflying,
  • bootless,
  • idealistic,
  • suspicious,
  • impractical,
  • anserine,
  • undiscerning,
  • simpleminded,
  • hard to swallow,
  • absolutely not,
  • contrary to reason,
  • fabulous,
  • odd,
  • pinheaded,
  • batty,
  • romantic,
  • Excluded,
  • featherbrained,
  • moonstruck,
  • unthinking,
  • reckless,
  • shameful,
  • unlikely,
  • hare-brained,
  • reasonless,
  • out of sight,
  • half-baked,
  • bombastic,
  • Daffy,
  • scandalous,
  • loopy,
  • zany,
  • undeserving,
  • unworkable,
  • rash,
  • unworthy,
  • giddy,
  • cockeyed,
  • worthless,
  • strange,
  • delusion,
  • pitiable,
  • Fatuitous,
  • absurd,
  • quibbling,
  • mad,
  • dolt,
  • offbeat,
  • dumb,
  • short-sighted,
  • goosy,
  • unperceiving,
  • unrealistic,
  • overpriced,
  • dreamlike,
  • improper,
  • flighty,
  • idiot,
  • mind-boggling,
  • playful,
  • screwy,
  • burlesque,
  • waggish,
  • cock-eyed,
  • oversight,
  • miss,
  • unsatisfactory,
  • unimpressive,
  • witty,
  • empty,
  • dreamy,
  • tall,
  • unproductive,
  • marvelous,
  • unearthly,
  • unearned,
  • florid,
  • absurdity,
  • usurious,
  • inflationary,
  • immoderate,
  • queer,
  • flimflam,
  • unnatural,
  • maggoty,
  • intemperate,
  • error,
  • undeserved,
  • unseemly,
  • aimless,
  • comic,
  • abnormal,
  • hopeless,
  • Crack-brained,
  • witless,
  • sappy,
  • out of the question,
  • unbecoming,
  • towering,
  • Misbecoming,
  • mistake,
  • screwball,
  • side-splitting,
  • erratic,
  • fantastical,
  • imbecile,
  • question,
  • fruitless,
  • lapse,
  • absurdness,
  • imprudent,
  • ill-advised,
  • overgrown,
  • Absurdities,
  • unwise,
  • imbecilic,
  • unthinkable,
  • askew,
  • featherheaded,
  • cutthroat,
  • baroque,
  • mistaken,
  • jerky,
  • desperate,
  • dimwit,
  • strained,
  • crotchety,
  • Doubtable,
  • unusual,
  • taking the cake,
  • Unowed,
  • Unmeet,
  • tomfool,
  • fallaciousness,
  • unreasoning,
  • droll,
  • wet,
  • falsehood,
  • doggerel,
  • gooselike,
  • baloney,
  • daft,
  • dopy,
  • childish,
  • gross,
  • ineffective,
  • mindless,
  • unimaginable,
  • myopic,
  • uncommon,
  • hollow,
  • chimeric,
  • oxymoronic,
  • nitwitted,
  • puerile,
  • anomalous,
  • softheaded,
  • rococo,
  • not on,
  • airheaded,
  • dotty,
  • visionary,
  • hard to believe,
  • dopey,
  • doubtful.

Antonyms for Preposterous:

• adj.

  • ridiculous, bizarre
    logical, serious, bad, sensible, sound, tenable, reasonable, poor, responsible, credible, wise, plausible, sane, practical, possible, balanced, plain, intelligent, believable, rational, realistic, smart, good.
  • Other antonyms:
    undeniable, earnest, demonstrated, established, substantial, consistent, sagacious, prudent, sane, realistic, true, indisputable, infallible, sapient, certain, indubitable, demonstrable, judicious, unquestionable, sage, incontrovertible, valid, incontestable, conceivable, well-advised, sensible.