Synonyms of preposterous

preposterous

adjective

pri-ˈpä-st(ə-)rəs 

1

as in absurd

conceived or made without regard for reason or reality

the idea that extraterrestrials built the pyramids is preposterous

Synonyms & Similar Words

• absurd
• bizarre
• foolish
• unreal
• insane
• fanciful
• crazy
• strange
• ridiculous
• nonsensical
• fantastic
• wild
• incredible
• grotesque
• curious
• implausible
• peculiar
• inconceivable
• odd
• funny
• off the wall
• weird
• unbelievable
• unthinkable
• ludicrous
• unimaginable
• outlandish
• eccentric
• extravagant
• laughable
• farcical
• wacky
• surreal
• quaint
• queer
• quirky
• outré
• kinky
• nightmarish
• out-of-the-way
• screwy
• kooky
• Alice-in-Wonderland
• way-out
• far-out
• dreamlike
• bizarro
• queerish
• Kafkaesque

Antonyms & Near Antonyms

• reasonable
• realistic

2

as in silly

showing or marked by a lack of good sense or judgment

a preposterous suggestion to go swimming in this freezing weather

Synonyms & Similar Words

• absurd
• silly
• foolish
• stupid
• insane
• crazy
• mad
• idiotic
• irrational
• ridiculous
• asinine
• nonsensical
• fatuous
• lunatic
• unreasonable
• simple
• zany
• fool
• harebrained
• dumb
• loony
• wacky
• unwise
• daft
• daffy
• nutty
• kooky
• simpleminded
• screwball
• crackpot
• senseless
• witless
• brainless
• wacko
• dippy
• cuckoo
• inept
• weak
• unreasoning
• cockeyed
• sappy
• barmy
• out to lunch
• dotty
• jerky
• weak-minded
• crackbrained
• batty
• gaga
• balmy
• slow
• half-baked
• loony tunes
• ludicrous
• illogical
• moronic
• bubbleheaded
• meshuga
• half-witted
• lunkheaded
• laughable
• thoughtless
• unreasoned
• featherheaded
• fallacious
• vacuous
• tomfool
• fruity
• farcical
• obtuse
• dense
• doltish
• imbecile
• unintelligent
• dull
• clueless
• dopey
• lamebrain
• opaque
• dunderheaded
• mindless
• feebleminded
• invalid
• dim
• brain-dead
• pinheaded
• unsound
• empty-headed
• softheaded
• thickheaded
• dorky
• oafish
• surd
• nonrational
• thick
• gormless
• soft
• clownish
• dim-witted
• notional
• knuckleheaded
• airheaded
• ill-advised
• chuckleheaded
• slow-witted
• birdbrained
• buffoonish
• boobish
• unconsidered
• chowderheaded

Antonyms & Near Antonyms

• sound
• sensible
• wise
• prudent
• reasonable
• sane
• judicious
• clever
• intelligent
• logical
• valid
• rational
• smart
• sagacious
• bright
• sage
• sapient
• brainy
• well-advised

3

as in ridiculous

so foolish or pointless as to be worthy of scornful laughter

the movie thriller had such a preposterous plot that we were on the edge of our seats snickering

Synonyms & Similar Words

• ridiculous
• absurd
• silly
• pathetic
• foolish
• ludicrous
• comical
• stupid
• unreasonable
• laughable
• farcical
• irrational
• risible
• dumb
• incredible
• derisive
• insane
• derisory
• crazy
• cockamamy
• for the birds
• fantastic
• idiotic
• asinine
• inane
• nonsensical
• fatuous
• mad
• moronic
• inconceivable
• unwise
• harebrained
• unbelievable
• imbecile
• unreal
• unrealistic
• illogical
• loony
• wacky
• simpleminded
• witless
• brainless
• daffy
• nutty
• kooky
• jerky
• cuckoo
• far-fetched
• half-baked
• senseless
• daft
• cockeyed
• screwball
• half-witted
• weak-minded
• balmy
• dotty

Antonyms & Near Antonyms

• serious
• earnest
• solemn
• reasonable
• logical
• realistic
• conceivable
• rational
• credible
• sensible
• believable

Example Sentences

Recent Examples of preposterous

Betting on the literal words coming out of someone's mouth has led to preposterous outcomes. — Bobby Allyn, NPR, 13 Aug. 2026

The biggest question for those debating whether to see this frisky and original rom-com starring San Francisco native Monica Barbaro and British of-the-moment actor Callum Turner might well be its preposterous premise. — Randy Myers, Mercury News, 5 Aug. 2026

Nothing has swirled more than appreciation — a sentiment Royals fans reciprocated on Tuesday night at Kauffman Stadium with a pre-game ceremony in Perez’s honor for the record-breaker that once would have seemed preposterous. — Vahe Gregorian, Kansas City Star, 4 Aug. 2026

Serious horology aficionados are used to waiting—even if lead times for coveted watches have become preposterous. — Paige Reddinger, Robb Report, 26 July 2026