BE NOT TO KNOW


Meaning of BE NOT TO KNOW in English

to have no way of realizing or being aware that you have done sth wrong :

'I'm sorry, I called when you were in bed.' 'Don't worry—you weren't to know.'

Oxford Advanced Learner's English Dictionary.      Оксфордский английский словарь для изучающик язык на продвинутом уровне.