mistake

(noun) a wrong action attributable to bad judgment or ignorance or inattention. Synonyms: error, fault. Examples: "He made a bad mistake." "She was quick to point out my errors." "I could understand his english in spite of his grammatical faults."

(noun) an understanding of something that is not correct. Synonyms: misunderstanding, misapprehension. Examples: "He wasn't going to admit his mistake." "Make no mistake about his intentions." "There must be some misunderstanding--i don't have a sister."

(noun) part of a statement that is not correct. Synonyms: error. Example: "The book was full of errors."

(verb) identify incorrectly. Synonyms: misidentify. Example: "Don't mistake her for her twin sister."

(verb) to make a mistake or be incorrect. Synonyms: err, slip.