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Dictionary.com
Definitions

by mistake

ADJECTIVE
accidentally
Synonyms
STRONGEST
unintentionally unwittingly
WEAK
fortuitously haphazardly
ADVERB
by chance
Synonyms
WEAK
accidentally as luck would have it by a fluke by coincidence for some reason fortuitously out of the clear blue sky unexpectedly unintentionally unwittingly
ADVERB
unawares
Synonyms
STRONG
short
WEAK
aback abruptly accidentally by accident by surprise carelessly ignorantly inadvertently mistakenly off guard sudden surprisingly unconsciously unexpectedly unintentionally unknowingly unprepared unready unwittingly
Antonyms
WEAK
consciously knowingly

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

"No one remained imprisoned by mistake: the people were released," said Morando.

From Barron's • Mar. 17, 2026

Microsoft has acknowledged an error causing its AI work assistant to access and summarise some users' confidential emails by mistake.

From BBC • Feb. 19, 2026

When these files were released, a number of things seemed to have been released by mistake.

From Slate • Feb. 4, 2026

For more than an hour, Trump repeatedly called Greenland Iceland by mistake, while demanding it be turned over to him.

From Los Angeles Times • Jan. 21, 2026

In her rare moments of lucidity she understood that this was not a nightmare and that she was not there by mistake.

From "The House of the Spirits: A Novel" by Isabel Allende