Blunder vs That was a mistake

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

Blunder

Top 2,000 (common)B1noun

That was a mistake

Top 5,000 (fairly common)
Most common: Blunder
 BlunderThat was a mistake
Pronunciation🇬🇧 //ˈblʌndə//🇺🇸 //ˈblʌndər//🇬🇧 //ðæt wəz ə mɪˈsteɪk//🇺🇸 //ðæt wəz ə mɪˈsteɪk//
MeaningA big mistake or careless error.An error or something wrong that was done.
ExampleHis explanation was full of blunders that made everyone confused.When I missed the deadline, I knew that was a mistake.
RegisterNeutralNeutral
How commonTop 2,000 (common)Top 5,000 (fairly common)
CEFR levelB1-
Part of speechnoun
Collocationsserious blunder, common blunder, make a blundermake a mistake, admit a mistake, correct a mistake
Antonymsaccuracy, perfection, success-
Common mistakesConfusing with 'fumble' which refers to a physical mistake rather than a mental error., Using 'blunder' only in formal situations; it can also be used in informal contexts., Overusing the word for small mistakes; it's meant for significant errors.Using past tense incorrectly, e.g., saying 'That is a mistake' when referring to a past action., Omitting the subject, leading to phrases like 'Was a mistake.', Confusing it with other expressions like 'That was wrong.'
Usage notesUse 'blunder' for mistakes that are noticeable and often embarrassing. It's suitable for most contexts but may sound too strong in casual conversation."That was a mistake" is often used to acknowledge an error. It's suitable for casual and formal conversations but may be less appropriate in very light-hearted contexts.

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Blunder
That was a mistake

Frequently asked questions: Blunder vs That was a mistake

What's the difference between Blunder and That was a mistake?

Blunder: A big mistake or careless error. That was a mistake: An error or something wrong that was done.

Which is more common: Blunder and That was a mistake?

Blunder is the most common in everyday English.

Can you show an example of each?

Blunder: His explanation was full of blunders that made everyone confused. That was a mistake: When I missed the deadline, I knew that was a mistake.

Can I use Blunder and That was a mistake interchangeably?

Not always. Blunder and That was a mistake 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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