What does mistaken mean?
Mistaken describes a belief, judgment, opinion, or identification that is incorrect because it rests on a false assumption. It commonly occurs in constructions such as "mistaken about," where something is incorrectly understood, and "mistaken for," where one person or thing is confused with another. The word is often used in measured, formal contexts, especially when discussing evidence, identity, or public perception: a witness may be mistaken about what they saw, or a stranger may be mistaken for a suspect. Mistaken can also function as the past participle of the verb "mistake." Unlike a stronger accusation such as false, it often suggests an honest error or misunderstanding rather than deliberate deception. In "if I'm mistaken," it functions as a conventional expression of uncertainty, allowing a speaker to qualify a claim without making a forceful assertion.
Incorrect in belief, judgment, or understanding; based on a false assumption.
"The doctor cautioned that the initial diagnosis had been mistaken."
Often used in the patterns "mistaken about" and "mistaken belief."
Incorrectly identified as or regarded as a particular person or thing.
"The child was mistaken for his older brother at the school gates."
The usual construction is "mistaken for" or "mistaken as."
The past participle of "mistake," used to form the passive voice and perfect tenses.
"The officers had mistaken the unmarked van for a delivery vehicle."
This form is normally used with the auxiliary "have" or "be" rather than as a finite verb on its own.
To be mistaken is not necessarily to make a mistake: a person can be mistaken about a fact without being careless or uninformed.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does mistaken come from?
The adjective developed from the verb "mistake," which comes from Old Norse mistaka, meaning "to take wrongly." In modern English, "mistaken" is the ordinary past participle of that verb, while the established adjective meaning "incorrect in judgment or identification" continues that older sense. The verb form "mistook" preserves the Old English-style vowel alternation in the past tense, reflecting the preterite and past-participle forms retained in the language.
Related word forms
How mistaken is actually used
The phrase "be mistaken about" is common in formal and informal English. "Mistaken for" specifically introduces an incorrect identification, while "mistaken" by itself usually describes an erroneous belief or judgment. The word is sometimes used in the idiom "if I'm mistaken," a polite way of introducing information that may be incorrect.
Easily confused with mistaken
Mistake is the noun or verb referring to an error or an act of misjudging, whereas mistaken is the adjective describing a false belief, judgment, or identification.