Unbelievable vs What a world

When to use each in English, with meaning, register, and examples.

Unbelievable

Top 1,000 (very common)

What a world

InformalTop 5,000 (fairly common)
Most formal: UnbelievableMost common: Unbelievable
 UnbelievableWhat a world
Pronunciation🇬🇧 //ʌn.bɪˈliː.və.bəl//🇺🇸 //ʌn.bɪˈlivə.bəl//🇬🇧 //wɒt ə wɜːld//🇺🇸 //wɑt ə wɜrld//
MeaningNot able to be believed; hard to accept as true.An expression of surprise or disbelief about life or a situation.
ExampleHis story about climbing Everest without oxygen was simply unbelievable.When I saw the price of that luxury car, I thought, 'What a world!'
RegisterNeutralInformal
How commonTop 1,000 (very common)Top 5,000 (fairly common)
Collocationsunbelievable story, unbelievable situation, unbelievable coincidence, unbelievable talent, unbelievable priceswhat a surprise, what a life, what a moment
Antonymscredible, believable, plausible-
Common mistakesConfused with 'incredible' - both mean similar things but can have different connotations., Used too casually in serious contexts., Often mispronounced by stressing the wrong syllable.Using it too seriously; it's meant to be light-hearted., Mispronouncing the phrase or not emphasizing the 'what'., Not using it in appropriate situations where surprise is evident.
Usage notesUsed to express astonishment or disbelief. It can be positive or negative depending on context (e.g., an unbelievable achievement vs. an unbelievable lie)."What a world" is often used to comment on surprising or outrageous events. It's informal, so avoid using it in formal contexts.

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Unbelievable
What a world

Frequently asked questions: Unbelievable vs What a world

What's the difference between Unbelievable and What a world?

Unbelievable: Not able to be believed; hard to accept as true. What a world: An expression of surprise or disbelief about life or a situation.

Which is more formal: Unbelievable and What a world?

Unbelievable is the most formal of these.

Which is more common: Unbelievable and What a world?

Unbelievable is the most common in everyday English.

Can you show an example of each?

Unbelievable: His story about climbing Everest without oxygen was simply unbelievable. What a world: When I saw the price of that luxury car, I thought, 'What a world!'

Can I use Unbelievable and What a world interchangeably?

Not always. Unbelievable and What a world are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.

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