Preposterous
adjective
Definition
1. (adjective) So unreasonable or unbelievable that it seems foolish — describes ideas, claims, or situations that simply don't make sense.
2. (adjective) Outrageous or absurd to the point that you can't take it seriously — often used dramatically, with anger or disbelief.
2. (adjective) Outrageous or absurd to the point that you can't take it seriously — often used dramatically, with anger or disbelief.
Context Alive
You're at a small restaurant with your friends and the waiter finally brings the bill. You look at it and freeze — they've charged you £28 for a single glass of water, labelled "sparkling spring water, imported from Fiji." You slide the bill across the table to your friend. She reads it, bursts out laughing, and says, "That's absolutely preposterous." You call the waiter over to question it, and he shrugs and points at a tiny line on the menu. Nobody wants to cause a scene, so you pay the bill, walk out, and agree on the way home that you're definitely never coming back to this place again.
Meanings
2 meanings 1 Absurd or Ridiculous (Adjective) Common ▼
This meaning is about ideas, claims, or situations that are so unreasonable they almost sound like a joke. Imagine a politician promising that under his plan, every citizen will receive a free luxury car within a year — economists shake their heads and call the promise preposterous because the numbers don't even come close to working. This is describing something that breaks the basic rules of logic or common sense. You might say "the idea that he wrote that book himself is preposterous" when a claim contradicts the evidence, or someone could say "her excuse was completely preposterous" about a story that fell apart the moment you questioned it. Or picture a court case where a lawyer argues that the cat opened the safe and stole the diamonds — the judge dismisses the argument as preposterous and moves on. The word suggests the speaker's reaction is one of amused disbelief — "that can't be true."
✏️ Preposterous sits between ridiculous (everyday, casual) and absurd (slightly more abstract and philosophical). It has a formal, slightly theatrical feel — using it can sound a bit dramatic or old-fashioned in a fun way. Common strengtheners: absolutely preposterous, utterly preposterous, completely preposterous. In informal speech, most people just say ridiculous.
2 Outrageous — Used With Indignation (Adjective) Common ▼
This meaning is about the dramatic emotional use — when something is so unfair, offensive, or over-the-top that the speaker is genuinely angry. Imagine a customer who's been waiting on hold for two hours only to be told she'll be charged extra for changing her flight — she hangs up, furious, and tells her husband the whole thing is preposterous. This is describing outrage, not just logical disbelief. You might hear "the price is preposterous" from someone who feels they're being robbed at a shop, or someone could say "it's preposterous to blame me for this" when rejecting an unfair accusation. Or think about a manager who learns his staff are being asked to work an extra weekend without pay — he storms into his boss's office and says the whole request is preposterous. The word carries real emotion: indignation, frustration, the feeling that someone is being taken for a fool.
✏️ This dramatic use is very common in British English especially — you'll hear it in news interviews, dramas, and everyday complaints. The phrase that's preposterous! (with emphasis) is a classic way to reject something firmly. Because it sounds a little theatrical, it can also be used humorously — exaggerating to show how silly a situation is.
Common Patterns
Basic Structures
be preposterous → the simplest structure — labelling something as absurd
The whole plan is preposterous.
preposterous + noun → standard adjective use before the thing being judged
He made a preposterous claim about curing cancer with tea.
sound preposterous → describes a claim that seems ridiculous when you hear it
The story sounds preposterous, but every detail is true.
Common Structures
absolutely / utterly preposterous → strong emphasis — completely absurd or outrageous
Charging £20 for parking is absolutely preposterous.
find something preposterous → to personally judge a claim or idea as ridiculous
Most scientists found the theory preposterous.
it is preposterous to + verb → formally rejecting an action or suggestion as absurd
It is preposterous to blame the interns for this mess.
Collocations
10 collocationsabsolutely preposterous
completely absurd, usually said with emphasis
utterly preposterous
formal, strong version of absolutely preposterous
completely preposterous
another intensifier — fully unreasonable
sound preposterous
to seem absurd when described
preposterous idea
a suggestion that's hard to take seriously
preposterous claim
a statement that contradicts logic or evidence
preposterous suggestion
a proposal too silly to consider
preposterous price
an amount that is shockingly high or unfair
preposterous story
a tale that sounds unbelievable
preposterous notion
formal — an absurd mental image or belief
Example Sentences
10 examples
1
The idea that he wrote that novel in one week is absolutely preposterous.
The claim that he produced that novel in a single week is completely absurd.
2
Paying £50 for a basic sandwich is preposterous.
Spending £50 on a plain sandwich is outrageous.
3
The lawyer called the whole accusation preposterous and demanded it be dropped.
The lawyer labelled the entire charge ridiculous and asked for it to be dismissed.
4
It's preposterous to expect students to finish a whole novel overnight.
It's unreasonable to demand that students complete an entire novel in one night.
5
The politician made several preposterous promises during the debate.
The politician made multiple unreasonable pledges during the discussion.
6
His excuse for being late sounded utterly preposterous.
His explanation for arriving late sounded completely ridiculous.
7
Most historians find that theory about the pyramids preposterous.
The majority of historians consider that theory about the pyramids absurd.
8
She refused the offer, calling it a preposterous insult.
She turned down the proposal, labelling it a ridiculous offence.
9
The prices at that resort are preposterous, but people still go there.
The rates at that resort are outrageous, yet guests still book rooms there.
10
It sounded preposterous at first, but every word of his story turned out to be true.
It seemed unbelievable in the beginning, but everything in his tale turned out to be accurate.
Synonyms & Antonyms
6 items
Synonymsabsurd
slightly more abstract and philosophical — often about logic, not outrage
ridiculous
the everyday, common version — much more casual
ludicrous
close in meaning, often adds a sense of mockery or laughter
Antonymsreasonable
describes something sensible and fair — the direct opposite
sensible
everyday word for an idea that follows common sense
plausible
describes something believable, even if not certain