BE WRONG, be in error, be under a misapprehension, be misinformed, be misguided; informal be barking up the wrong tree, get the wrong end of the stick.
2192; headword
BE MISTAKEN
Meaning of BE MISTAKEN in English
Concise Oxford thesaurus English vocabulary. Краткий оксфордский словарь английского языка тезаурус. 2012