Grammar fix
mistake someone or something for another
identify wrongly
To wrongly think that one person or thing is another person or thing.
How oftenCommon
LevelB2
Used inSpeech & writing
Hear it in context
Notice where the phrase sounds natural.
In the dim light, I mistook the coat on the chair for a person.
I once mistook a neighbour for my uncle because they had the same coat and were walking away from me.
Fix the pattern
One small grammar move makes it sound right.
Not: I mistook her as her sister.
Say: I mistook her for her sister.
Use the preposition 'for' after 'mistake' in this meaning.
Don't confuse it
Other ways to say it
Think one person or thing is another
How formalCasualMore formal
muddle upEspecially British: confuse names, people, or similar things.mix upConfuse two people or things with each other.
mistake someone or something for anotherYou're here · Name both: 'I mistook her for her sister.'